Submitted by Marcos Anselmo (marcos.anselmo@unipampa.edu.br) on 2016-04-07T17:26:59Z No. of bitstreams: 1 Franciele Donato.pdf: 1097306 bytes, checksum: d397f421e694919bc9400a3137762b3e (MD5) / Made available in DSpace on 2016-04-07T17:27:00Z (GMT). No. of bitstreams: 1 Franciele Donato.pdf: 1097306 bytes, checksum: d397f421e694919bc9400a3137762b3e (MD5) Previous issue date: 2013-01-17 / A depressão é um transtorno mental comum associado a um significativo impacto negativo na qualidade da vida. Morbidade/mortalidade e função cognitiva. A teoria das monoaminas da depressão postula que esta doença resulta de uma deficiência na atividade monoaminérgica no cérebro. No entanto, outros sistemas neurais e processos bioquímicos, como o estresse oxidativo, parecem estar envoltos na sua patogênese. Os objetivos desse estudo foram investigar o efeito tipo antidepressivo e toxidade aguda do fenilselenometil-..-triazol(Se-TZ). (um suposto orgânico heterocíclico contendo selênio), administrado pela via oral em camundongos. Os resultados obtidos evidenciaram que a administração de Se-TZ, reduziu significativamente o tempo de imobilidade no teste de suspenção da cauda (TSC), sem alterar a atividade locomotora e exploratória no teste de campo aberto (tca). O efeito tipo antidepressivo de Se-TZ no TSC foi bloqueado pelo pré-tratamento dos camundongos com SCH23390 (0,05 mg/kg, s.c., antagonista seletivo do receptor D1), sulpirida (50 mg/kg, i.p.. antagonista seletivo do receptor D2) e metisergida (2mg/kg, s.c.. antagonista não seletivo dos receptores 5-HT), mas não com prazosin (1 mg/kg, i.p, antagonista de receptores α1- adrenérgico), ioimbina (1 mg/kg i.p., antagonista de receptores α2-adrenérgicos) e propranolol (2 mg/kg, i.p, antagonista não seletivo β-adrenérgico). A determinação dos níveis de neurotransmissores monoaminérgicos e seus metabólitos colaborou com os resultados obtidos anteriormente no TSC. Neste contexto, o Se-TZ, aumentou os níveis dos neurotransmissores monoaminérgicos dopamina (DA) e serotonina (5-HT) no córtex cerebral e no hipocampo. enquanto que os níveis de norepinefrina (NE), não foram alterados. Este estudo também mostrou que 72 horas após a administração do Se-TZ, os parâmetros de toxidade aguda aspartato aminotransferase (AST), alanina aminotransferase (ALT) uréia e creatinina, não foram alterados além disso, os resultados evidenciaram que a exposição ao Se-TZ causou um aumento significativo na atividade de catalase (CAT) no córtex cerebral e no hipocampo, no entanto, a glutadiona S-transferase (GST) aumentou apenas no córtex cerebral. A peroxidação lipídica e os níveis de tióis não-protéicos (NPSH) não foram alterados. Estes resultados sugerem que o Se-TZ apresentou efeito tipo antidepressivo. Mediado através do sistema neurotransmissor dopaminérgico (D1 e D2) e serotoninérgicos, sem causar toxidade aguda nos marcadores bioquímicos de lesão hepática e renal avaliados. / Depression is a common mental disorder associated whth a signigicant negative impact n quality of life, morbidity, and cognitive function. The monoamine theory of depression postultes that this disease results from a deficiency of brain monoaminergie activity, however other neural systems and biochemical process, like oxidative stress, appear to be involved in its pathogenesis. The aims of the study were investigated the antidepressant like effect, acute toxicity of 4-phenyl-1-(phenylselanylmenthyl)-1,2,3-trizole (Se-TZ), (an organocompounds selenium-containing heterocycles), administered by oral route, in mice. The results evidenced that administration of Se-TZ, significantly reduced immobility time in tail suspension test (TST), without altering locomotor and exploratory activity in the open-field test (OFT). The antidepressant-like effect of Se-TZ ib the TST was prevented by pretreatment of miche with SCH23390 (0,5 g/Kg, s. s, selective D1 receptor antagonist), sulpiride (50 mg/Kg, i.p., selective D2 receptor antagonist) and methysegide ( 2 mg/Kg, s.c., non-selective 5-HT receptors antagonist), but not with prazosin ( 1 mg/Kg, i.p., an α 1 –adrenoreceptor antagonist), yohimbine ( 1 mg/Kg, i.pi.; an α 2-adrenoreceptor antagonist) and propranolol (2 mg/Kg i.p.; β-adrenoreceptor antagonist). The determination of levels of monoamine neurotransmitters and their metabolites cooperating with results obtained previously in TST. In this context, the Se-TZ, increased monoamine neurotransmitters dopamine (DA) an serotonin (5-HT) levels in the cerebral cortex an hippocampus, whereas norepinephrine (NE) levels, were not altered. This study also showed that 72 hours after administration of single oral dose of Se-TZ, the paramenters of acute toxicity to biochemical makers hepatic damage: aspartate aminotransferase (AST) and alanine aminotransferase (ALT) and renal: urea and creatinine, were not altered. Furthermore, the results evidenced that exposure to Se-TZ caused a significant increase in the catalase (CAT) activity in the cerebral cortex and hippocampus, however the glutathione S-tranferase CGST) activity increased only in cerebral cortex. The lipid peroxidation and NPSH (non protein thiols) levels, were not changed. These results suggest that the Se-TZ presented antidepressant effect, mediated through the dopaminiergie (D1 and D2) and serotonergie neurotransmitter systems, without causing acute toxicity in biochemical makers of liver and kidney damage evaluated.

Στο κεντρικό νευρικό σύστημα υπάρχουν διακριτές περιοχές με αμιγώς αισθητική λειτουργία κι άλλες με αμιγώς κινητική. Υπάρχουν ωστόσο και περιοχές, των οποίων η λειτουργία είναι να συντονίζουν ολόκληρο το νευρικό σύστημα. Σημαντικό ρόλο σε αυτόν το συντονισμό έχουν οι χολινεργικοί και οι μονοαμινεργικοί νευρώνες, οι οποίοι με τους νευροδιαβιβαστές που εκκρίνουν, μπορούν να ελέγχουν μερικές από τις πιο περίπλοκες λειτουργίες του ΚΝΣ (μνήμη, δραστηριοποίηση, διάθεση, libido και πολλές άλλες). Η Ρ4 είναι μια πρωτεΐνη που ανακαλύφθηκε μόλις το 2004. Ανήκει στην οικογένεια των μεταφορέων SLC10 και μοιράζεται αρκετά κοινή δομή με τα υπόλοιπα μέλη, παρόλο που εκφράζεται σε εντελώς διαφορετικές περιοχές από αυτά. Η μοναδικότητα της Ρ4 έγκειται στο ότι είναι ένας διαμεμβρανικός νευροδιαβιβαστής που εντοπίζεται τόσο στους χολινεργικούς όσο και στους μονοαμινεργικούς νευρώνες, γεγονός που την καθιστά τον μόνο διαβιβαστή με διτή παρουσία και στα δύο αυτά συστήματα. Ωστόσο, δεν υπάρχουν ακόμη πολλές πληροφορίες για τον ακριβή εντοπισμό της σε αυτούς τους νευρώνες ούτε για το μήνυμα το οποίο μεταφέρει. Προηγούμενα πειράματα έδειξαν ότι η Ρ4 σχετίζεται με τον έλεγχο στην έκκριση της ντοπαμίνης. Η αρχική μας υπόθεση είναι ότι αυτό επιτυγχάνεται μέσω κάποιας αλληλεπίδρασης της Ρ4 και της VMAT2, η οποία είναι υπεύθυνη για την απελευθέρωση ντοπαμίνης από τα συναπτικά κυστίδια. Μια τέτοια σχέση, θα μπορούσε να δικαιολογηθεί αν οι δύο αυτές πρωτεΐνες εντοπίζονται στο ίδιο συναπτικό κυστίδιο. Προκειμένου να επαληθεύσουμε αυτήν την υπόθεση, χρησιμοποιήσαμε τη μέθοδο της Ανοσοκατακρήμνησης. Τα αποτελέσματα μέχρι στιγμής είναι ενθαρρυντικά και με μερικές βελτιστοποιήσεις, η μέθοδος αυτή θα μπορούσε να επαληθεύσει αυτήν την υπόθεση. Προκειμένου να διερευνηθεί περαιτέρω η λειτουργία της Ρ4, μελέτες συμπεριφοράς καθώς και φαρμακολογικές μελέτες πραγματοποιήθηκαν σε γενετικά τροποποιημένα ποντίκια, τα οποία δεν μπορούν να συνθέσουν Ρ4. Τα αποτέλεσματα έδειξαν ότι η Ρ4 δεν επηρεάζει τη λειτουργία της μνήμης, ωστόσο ίσως σχετίζεται με την ανάληψη πρωτοβουλίας και την επιθυμία ανταμοιβής. Παράλληλα, οι δοκιμές με αμφεταμίνη επαλήθευσαν ότι η Ρ4 σχετίζεται με την έκκριση ντοπαμίνης. Μελέτες με φλουοξετίνη έδειξαν πιθανή επίδραση της P4 στην έκκριση σεροτονίνης, η οποία ωστόσο δεν ήταν αρκετά ξεκάθαρη προς το παρόν. Τα πειράματα αυτά αποκάλυψαν ακόμη παράγοντες οι οποίοι μπορούν να επηρεάσουν την έκβαση των δοκιμών σε γενετικά τροποποιημένα ποντίκια και οι οποίοι θα πρέπει να λαμβάνονται υπόψη κατά το σχεδιασμό μελλοντικών πειραμάτων. Οι ιδιότητες της Ρ4 δεν έχουν κατανοηθεί ακόμα πλήρως και απαιτούνται πολλά επιπλέον πειράματα προκειμένου αυτές να αποκαλυφθούν. Νέες φαρμακολογικές μελέτες έχουν ήδη σχεδιαστεί, ενώ παράλληλα σύγχρονες μοριακές τεχνικές έχουν επιστρατευθεί ώστε να ρίξουν φως στην ακριβή της τοποθεσία. / This master thesis summarizes the efforts to identify the location and the behavioural effect of P4, a recently discovered protein. P4 belongs to the family of sodium‐dependent bile acid transporters (SLC10), whose first two members are expressed in the gastrointestinal system. However, P4 itself shows a wide expression pattern in various areas of the Central Nervous System. According to electron microscopy, in situ and immunohistochemistry studies, P4 is expressed specifically in both the cholinergic and the monoaminergic terminals, two systems that are responsible for various neurologic and psychiatric disorders. Previous cocaine provocation in KO animals indicated a possible effect of P4 in the release of dopamine. Since VMAT2 is responsible for the transfer of dopamine into the synaptic vesicles, the relation between P4 and VMAT2 needs to become clear. Using Immunoprecipitation, we tried to distinguish if P4 and VMAT2 share the same synaptic vesicle. Moreover, studies in animal models were used in order to unravel the function of P4: the Radial Arm Maze assessment showed no influence of P4 on memory but a possible effect in the reward system, amphetamine provocation showed that KO animals are more affected by amphetamine, while fluoxetine provocation indicated a possible effect of P4 in serotoninergic neurons. Tests in animals with different genetic origin revealed several factors that can affect the final outcome of these studies (age, weight and housing). All this data will help us design our future studies and cast more light in the properties of P4.

Submitted by Erika Demachki (erikademachki@gmail.com) on 2016-08-05T20:21:29Z No. of bitstreams: 2 Dissertação - Danillo Ramos de Oliveira - 2016.pdf: 3328781 bytes, checksum: a9a77fd6d62aba93833d8451de1e5f75 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2016-08-08T14:14:43Z (GMT) No. of bitstreams: 2 Dissertação - Danillo Ramos de Oliveira - 2016.pdf: 3328781 bytes, checksum: a9a77fd6d62aba93833d8451de1e5f75 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2016-08-08T14:14:43Z (GMT). No. of bitstreams: 2 Dissertação - Danillo Ramos de Oliveira - 2016.pdf: 3328781 bytes, checksum: a9a77fd6d62aba93833d8451de1e5f75 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2016-03-31 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Spiranthera odoratissima A. St.-Hil., popularly known as “manacá”, is a vegetal specie found in Cerrado regions. The chemical composition of essential oil of “manacá” (OEM) by gas chromatography and mass spectrometry (GC/MS) identified -caryophyllene (BCP) as the majority constituent. Pre-clinical studies indicated the anxiolytic like effect of OEM is associated with serotonergic system. Some data revealed that depression and anxiety disorders often coexist together instead only one in the patient and some drugs are effective for both disturbs. In this context, we created the hypothesis that OEM and BCP should present antidepressant like effect. This study was conducted for evaluate the antidepressant like activity of OEM and the phytoconstituent β-caryophyllene and verified the possible mechanisms involved in this activity. Male Albino Swiss mice were used in the open field (OFT), forced swim (FST) and tail suspension test (TST). The animals were treated with increasing doses of OEM (125, 250 and 500 mg/kg) and of BCP (25, 50, 70, 100 and 140 mg/kg). The treatment with OEM at doses of 250 and 500 mg/kg, BCP at doses of 50, 70 and 100 mg/kg reduced the immobility time of animals in the TST without alteration in the exploratory activity in the OFT. The dose of 500 mg/kg of OEM and dose of 100 mg/kg of BCP showed the best effect and were chosen to continue the study. Possible alterations in the levels of serotonin (5 – HT), noradrenaline (NE) and in the brain derived neurotrophic factor (BDNF) were verified in the mechanisms of action. The anti-immobility time of OEM was reverted by the pre-treatment with NAN- 190 (0,5 mg/kg i.p., 30 minutes before – 5-HT1A antagonist), PCPA (100 mg/kg i.p., during 4 days – inhibitor of serotonin synthesis), AMPT (100 mg/kg i.p., 4 h before – inhibitor of catecholamines), ioimbine (1 mg/kg i.p., 15 minutes before - 2 adrenergic antagonist) and propranolol (2 mg/kg i.p., 15 minutes before -  adrenergic antagonist), but was not reverted by the pretreatment with prazosin (1 mg/kg i.p., 15 minutes before - α1 adrenergic antagonist), suggesting the involvement of serotonergic and catecholaminergic systems in the antidepressive like activity. About the BCP, the pre-treatment with NAN-190, in the conditions described above, did not block the antidepressive like activity of this compound, suggesting the absence of participation of serotonergic system in this activity. The prazosin did not reverse the effect of BCP. However, the previous administration of AMPT, ioimbine and propranolol in the same conditions described above, prevents the antidepressant like activity of BCP in the FST, suggesting the involvement of catecholamines, specifically of NE, in the antidepressive like effect of the BCP. In relation with the capacity to alter the hipocampal levels of BDNF, BCP showed this activity after 14 days of treatment. In this sense we conclude that OEM and the phytoconstituent (BCP) showed antidepressant like effect with involvement of serotonergic system and of the 5-HT1A receptor in the action of OEM, but not of the BCP. Moreover, a activation of α2 and β-adrenergic receptors, but not of 1, are involved in the activity of OEM and of the BCP found in this study. Additionally, the increase in the hippocampal levels of BDNF, can be the responsible, at least in part, with the antidepressant like activity of BCP. / A espécie vegetal Spiranthera odoratissima A. St.-Hil., popularmente conhecida como manacá, é um arbusto encontrado em região de Cerrado. A análise da composição química do óleo essencial das folhas de manacá (OEM) por Cromatografia Gasosa acoplada à espectrometria de Massas (CG/EM) identificou β- cariofileno (BCP) como fitoconstituinte majoritário. Estudos pré-clínicos indicam que o OEM possui atividade tipo ansiolítica, havendo o envolvimento do sistema serotoninérgico nessa ação. Sabendo que os transtornos depressivos e os de ansiedade muitas vezes coexistem juntos, ao invés de afetar o paciente de forma isolada, e que alguns fármacos são eficazes no tratamento de ambos os distúrbios, resolvemos testar a hipótese de que o OEM e o BCP poderiam apresentar efeito tipo antidepressivo. O presente trabalho investigou a atividade do tipo antidepressiva do OEM e do fitoconstituinte BCP, e verificou o envolvimento do sistema monoaminérgico no efeito destes. Adicionalmente, os níveis hipocampais do fator neurotrófico derivado do cérebro (BDNF) foram quantificados após 14 dias de tratamento com BCP 100 mg/kg. Foram utilizados camundongos albinos Swiss machos nos testes do campo aberto (TCA), nado forçado (TNF) e suspensão pela cauda (TSC). Os animais foram tratados, pela via oral, com doses crescentes do OEM (125, 250 e 500 mg/kg) e de BCP (25, 50, 70, 100 e 140 mg/kg). O tratamento tanto com o OEM nas doses de 250 e 500 mg/kg, quanto com BCP nas doses de 50, 70 e 100 mg/kg reduziram o tempo de imobilidade dos animais no TNF, sem alterar a atividade exploratória no TCA, sendo que a dose de 500 mg/kg do OEM e 100 mg/kg de BCP apresentaram melhor efeito e foram escolhidas para dar continuidade ao estudo. Possíveis alterações nos níveis de serotonina (5-HT), norepinefrina (NE) e do fator neurotrófico derivado do cérebro (BDNF) foram verificadas no estudo dos mecanismos de ação. O efeito anti-imobilidade do OEM foi revertido pelo pré- tratamento com NAN-190 (0,5 mg/kg i.p., 30 minutos antes – antagonista 5-HT1A), PCPA (100 mg/kg i.p., durante 4 dias – inibidor da síntese de serotonina), AMPT (100 mg/kg i.p., 4 h antes – inibidor da síntese de catecolaminas), ioimbina (1 mg/kg i.p., 15 minutos antes – antagonista α2-adrenérgico) e propranolol (2 mg/kg i.p., 15 minutos antes – antagonista β-adrenérgico), mas não foi revertido pelo pré- tratamento com prazosina (1 mg/kg i.p., 15 minutos antes – antagonista α1- adrenérgico), sugerindo o envolvimento do sistema serotoninérgico e catecolaminérgico na atividade observada. Em relação ao BCP, o pré-tratamento com NAN-190, nas mesmas condições descritas acima, não bloqueou a atividade tipo antidepressiva deste composto, sugerindo a ausência da participação do sistema serotoninérgico nessa ação. A prazosina também não reverteu o efeito de BCP. Entretanto, a administração prévia, de AMPT, ioimbina e propranolol, nas mesmas condições supracitadas, impediu a ação tipo antidepressiva de BCP no TNF, sugerindo o envolvimento de catecolaminas, especificamente de NE, no efeito do fitoconstituinte. Quanto à capacidade de aumentar os níveis hipocampais BDNF, BCP se mostrou ativo após tratamento repetido por 14 dias. Deste modo, concluímos que o OEM e BCP apresentaram efeito do tipo antidepressivo, havendo participação do sistema serotoninérgico e do receptor 5-HT1A na ação do OEM, mas não na de BCP. Além disso, uma ativação de receptores α2 e β-adrenérgicos, mas não de α1, parece estar envolvida nas ações do OEM e de BCP encontradas neste estudo. Adicionalmente, um aumento no nível hipocampal de BDNF, parece ser responsável, ao menos em partes, pela ação do tipo antidepressiva de BCP.

Patients with Rett Syndrome (RTT) show severe breathing disorders in addition to other neuropathological features, contributing to the high incidence of sudden unexplained death and abnormal brain development. However, the molecular and cellular mechanisms underlying the breathing disorders are still unknown. Recent studies indicate that the dysfunction of brainstem norepinephrine (NE) systems are closely associated with breathing disorders in RTT patients as well as its mice model, the Mecp2-null (Mecp2─/Y) mice. This as well as the fact the major group of NE-ergic neurons in the locus coeruleus (LC) is CO2 chemosensitive suggests that the breathing disorders in RTT may be related these LC neurons. To test this hypothesis, we took a multidisciplinary approach and systematically studied these neurons using molecular biology, in-vitro brain slices, acutely dissociated neurons, immunocytochemistry, and whole-body plethysmograph. To facilitate the electrophysiological studies, we developed a new strain of transgenic mice with GFP expression selectively in the LC neurons of both WT and Mecp2─/Y mice. Breathing activity of the Mecp2─/Y mice showed selective disruptions in responses to mild hypercapnia. The defect was alleviated with the NE uptake blocker desipramine, suggesting the involvement of NE in central CO2 chemosensitivity. In the LC region, the expressions of tyrosine hydroxylase (TH) and dopamine beta-hydroxylase (DBH) at both protein and mRNA levels reduced by ~50% in Mecp2─/Y mice. No evidence was found for selective deficiency in TH- or DBH-containing neurons in Mecp2─/Y mice, and no major loss of NE-ergic LC cells were found, indicating that the NE defect is likely to result from deficient expression of biosynthetic enzymes rather than a loss of neurons in the LC. Several intrinsic membrane properties were abnormal in Mecp2─/Y LC neurons in comparison to wild type cells, including stronger inward rectification, shorter time constant, extended action potential duration, smaller amplitude of medium afterhyperpolarization (AHP) and over-expression of fast AHP. These abnormalities seem to be associated with the altered K+ and Na+ currents. Most importantly, Mecp2─/Y LC neurons displayed defective CO2 chemosensitivity in agreement of in vivo CO2 response, likely due to excessive expression of the homomeric Kir4.1 channel. Thus, it seems that the global effect of MeCP2 on the A6 NE system contributes to the impaired systemic CO2 response as well as the breathing irregularities in Mecp2─/Y mice. Such an alteration allowed CO2 to be detected only when hypercapnia became severe, leading to periodical hyper- and hypoventilation. These findings not only provide a novel etiology for the breathing disturbances of Mecp2─/Y mice but also show direct evidence for the first time on a molecular mechanism for the central CO2 chemosensitivity.

O objetivo deste trabalho foi ampliar o estudo do mecanismo de ação antidepressivo de Hypericum polyanthemum (POL) e de seu composto derivado da classe dos floroglucinóis uliginosina B (ULI). Considerando o potencial desta planta para o desenvolvimento de novos fármacos, realizou-se um estudo pré-clínico de toxicidade aguda e doses repetidas de POL em camundongos. A administração via oral (v.o.) do extrato ciclo-hexano de POL (90 mg/kg) foi capaz de reduzir significativamente o tempo de imobilidade de ratos e camundongos no teste de natação forçada (TNF). A administração de ULI (10 mg/kg, v.o.) igualmente reduziu o tempo de imobilidade no TNF e também no teste de suspensão pela cauda (TSC). A administração simultânea (v.o), das subdoses de POL (45 mg/kg) e ULI (5 mg/kg) foram capazes de potencializar o efeito antidepressivo das subdoses de imipramina (10 mg/kg), bupropiona (3 mg/kg) e fluoxetina (15 mg/kg), no TNF em camundongos. O pré- tratamento de camundongos, pela via intraperitoneal, com SCH 23390 (antagonista de receptor dopaminérgico D1); sulpirida (antagonista de receptor dopaminérgico D2); prazosin (antagonista de receptor α1-adrenérgico); ioimbina (antagonista de receptor α2-adrenérgico) e p-clorofenilalanina metil éster (pCPA- inibidor da síntese de serotonina (5-HT), preveniu o efeito anti-imobilidade de ULI no TNF. In vitro, ULI inibiu a recaptação sinaptossomal de dopamina ([3H]-DA), noradrenalina ([3H]-NA) e serotonina ([3H]-5-HT), sem ligação aos transportadores, e isto foi demonstrado através das diferentes concentrações de ULI que não afetaram a ligação de [3H]- mazindol, [3H]-nisoxetina e [3H]-citalopram aos sítios de recaptação de DA, NA e 5- HT, respectivamente. Estes resultados sugerem que ULI tem ação não-seletiva sobre o sistema monoaminérgico, o que pode representar um novo composto com inibição tripla da recaptação; além disso possui mecanismo de ação diferente dos antidepressivos clássicos, inibindo a recaptação das monoaminas sem se ligar aos respectivos sítios específicos dos transportadores. Também realizou-se estudo bioquímico da atividade da Na+,K+-ATPase em córtex cerebral e hipocampo de camundongos. O tratamento agudo e repetido por via oral (3 dias, 1 x ao dia) aumentou a atividade desta enzima em córtex cerebral de camundongos em diferentes tempos. ULI não alterou a atividade da Na+,K+-ATPase em hipocampo dos camundongos, e esse resultado corrobora com a hipótese de que ULI pode estar contribuindo para a manutenção da excitabilidade neuronal estimulando esta enzima, e agindo seletivamente no córtex cerebral. Além disso, investigou-se o papel de ULI sobre os canais de sódio dependentes de voltagem (Na+), através da pré-administração de veratrina (ativador de canal de Na+). A veratrina bloqueou o efeito antidepressivo de ULI no TNF e este resultado indica a possibilidade de ULI estar bloqueando os canais de Na+ alterando o gradiente iônico através da estimulação da atividade da Na+,K+-ATPase e, prejudicando ou inibindo a recaptação das monoaminas. Nos experimentos de toxicidade, as mudanças fisiológicas, bioquímicas e histopatológicas mais pronunciadas foram observadas nos camundongos que receberam POL nas doses 5 e/ou 10 vezes maiores que a dose efetiva no TNF em camundongos. Entretanto, POL apresenta constituição química diferente de H. perforatum, sugerindo baixo risco desta espécie em relação à fototoxicidade (ausência de hipericina). Através dos dados obtidos neste estudo, acredita-se que POL pode se tornar uma espécie promissora no desenvolvimento de um novo fitoterápico com ação neuroativa. A inibição da recaptação das monoaminas pode estar relacionada a uma alteração do gradiente iônico de Na+, através da estimulação da atividade da Na+,K+-ATPase, o que leva a crer que ULI possui um perfil de ação lamotrigina-like. Dessa forma, ULI torna-se um novo e promissor padrão molecular de substância com atividade no sistema nervoso central. / The aim of this work was to continue studying the antidepressant mechanism of Hypericum polyanthemum (POL) and its compound derived from phloroglucinols class uliginosin B (ULI). Considering the potential for development of new drugs with this plant, a preclinical study of toxicity with POL was accomplished, administering acute and repeated-doses in mice. The cyclo-hexane extract administration by oral route (p.o.) of POL (90 mg/kg) was able to significantly reduce the immobility time of rats and mice in the forced swimming test (FST). ULI (10 mg/kg, p.o.) also produced a reduction in immobility time in two models predictive of antidepressant activity in mice, FST and the tail suspension test (TST). Simultaneously administration (p.o) of subeffective doses of POL (45 mg/kg) and ULI (5 mg/kg) were able to potentiate the antidepressant effect of subeffective dose of imipramine (10 mg/kg), bupropion (3 mg/kg ) and fluoxetine (15 mg/kg), in the mouse FST. The pretreatment of mice, by i.p. route, with SCH 23390 (dopamine D1 receptor antagonist); sulpiride (dopamine D2 receptor antagonist); (α1 adrenoceptor antagonist); yohimbine (α2 adrenoceptor antagonist) and p-chlorophenylalanine methyl ester (pCPA- an inhibitor of serotonin (5-HT) synthesis) prevented anti- immobility effect of ULI in FST. In vitro, ULI inhibited synaptosomal uptake of dopamine ([3H]-DA), noradrenaline ([3H]-NA) and 5-HT ([3H]-5-HT), without binding with monoaminergic transporters, and this was demonstrated by different concentrations of ULI that did not affect the binding of [3H]-mazindol, [3H]-nisoxetine and [3H]-citalopram to DA, NA and 5-HT uptake sites, respectively. These results suggest that ULI has non-selective action on the monoaminergic system, which may represent a new compound with triple reuptake inhibition; furthermore, ULI has a mechanism of action different from the classical antidepressants by inhibiting monoamine reuptake without bind to respective neurotransporters. In addition we have performed a biochemical study for activity of Na+, K+-ATPase in cerebral cortex and hippocampus of mice. Acute and repeated oral treatment (3 days, 1 x per day) increased enzyme activity in cortex at different times. ULI did not alter Na+, K+- ATPase activity in hippocampus, and this result confirms the hypothesis that ULI can be contributing to the maintenance of neuronal excitability by stimulating this enzyme, and acting selectively in cerebral cortex. Moreover, we investigated the role of ULI on voltage-gated sodium channels (Na+), through pre-administration of veratrine ( Na+ channel oppener). Veratrine was able to abolish the antidepressant effect of ULI in TNF and this result indicates the possibility that ULI blocks the Na+ channels by altering the ionic gradient through the stimulation of Na+, K+-ATPase and impairing or inhibiting the reuptake of monoamines. In toxicity experiments, the more pronounced physiological, biochemical and histopathological changes were observed in mice that received POL at doses 5 and/or 10 fold higher than the effective dose in TNF. However, POL has chemically different from H. perforatum, suggesting low risk of this species in relation to phototoxicity (absence of hypericin). Considering all results, we supposed that POL could be a product with potential for the development of new drugs. The monoamine reuptake inhibition can be related to a change on the gradient of Na+ ion, by stimulation of Na+, K+-ATPase, which suggests that ULI has a lamotrigine-like profile. Therefore, we suggest that phloroglucinol derivative ULI represents a promising new molecular pattern with central nervous system activity.

O objetivo deste trabalho foi ampliar o estudo do mecanismo de ação antidepressivo de Hypericum polyanthemum (POL) e de seu composto derivado da classe dos floroglucinóis uliginosina B (ULI). Considerando o potencial desta planta para o desenvolvimento de novos fármacos, realizou-se um estudo pré-clínico de toxicidade aguda e doses repetidas de POL em camundongos. A administração via oral (v.o.) do extrato ciclo-hexano de POL (90 mg/kg) foi capaz de reduzir significativamente o tempo de imobilidade de ratos e camundongos no teste de natação forçada (TNF). A administração de ULI (10 mg/kg, v.o.) igualmente reduziu o tempo de imobilidade no TNF e também no teste de suspensão pela cauda (TSC). A administração simultânea (v.o), das subdoses de POL (45 mg/kg) e ULI (5 mg/kg) foram capazes de potencializar o efeito antidepressivo das subdoses de imipramina (10 mg/kg), bupropiona (3 mg/kg) e fluoxetina (15 mg/kg), no TNF em camundongos. O pré- tratamento de camundongos, pela via intraperitoneal, com SCH 23390 (antagonista de receptor dopaminérgico D1); sulpirida (antagonista de receptor dopaminérgico D2); prazosin (antagonista de receptor α1-adrenérgico); ioimbina (antagonista de receptor α2-adrenérgico) e p-clorofenilalanina metil éster (pCPA- inibidor da síntese de serotonina (5-HT), preveniu o efeito anti-imobilidade de ULI no TNF. In vitro, ULI inibiu a recaptação sinaptossomal de dopamina ([3H]-DA), noradrenalina ([3H]-NA) e serotonina ([3H]-5-HT), sem ligação aos transportadores, e isto foi demonstrado através das diferentes concentrações de ULI que não afetaram a ligação de [3H]- mazindol, [3H]-nisoxetina e [3H]-citalopram aos sítios de recaptação de DA, NA e 5- HT, respectivamente. Estes resultados sugerem que ULI tem ação não-seletiva sobre o sistema monoaminérgico, o que pode representar um novo composto com inibição tripla da recaptação; além disso possui mecanismo de ação diferente dos antidepressivos clássicos, inibindo a recaptação das monoaminas sem se ligar aos respectivos sítios específicos dos transportadores. Também realizou-se estudo bioquímico da atividade da Na+,K+-ATPase em córtex cerebral e hipocampo de camundongos. O tratamento agudo e repetido por via oral (3 dias, 1 x ao dia) aumentou a atividade desta enzima em córtex cerebral de camundongos em diferentes tempos. ULI não alterou a atividade da Na+,K+-ATPase em hipocampo dos camundongos, e esse resultado corrobora com a hipótese de que ULI pode estar contribuindo para a manutenção da excitabilidade neuronal estimulando esta enzima, e agindo seletivamente no córtex cerebral. Além disso, investigou-se o papel de ULI sobre os canais de sódio dependentes de voltagem (Na+), através da pré-administração de veratrina (ativador de canal de Na+). A veratrina bloqueou o efeito antidepressivo de ULI no TNF e este resultado indica a possibilidade de ULI estar bloqueando os canais de Na+ alterando o gradiente iônico através da estimulação da atividade da Na+,K+-ATPase e, prejudicando ou inibindo a recaptação das monoaminas. Nos experimentos de toxicidade, as mudanças fisiológicas, bioquímicas e histopatológicas mais pronunciadas foram observadas nos camundongos que receberam POL nas doses 5 e/ou 10 vezes maiores que a dose efetiva no TNF em camundongos. Entretanto, POL apresenta constituição química diferente de H. perforatum, sugerindo baixo risco desta espécie em relação à fototoxicidade (ausência de hipericina). Através dos dados obtidos neste estudo, acredita-se que POL pode se tornar uma espécie promissora no desenvolvimento de um novo fitoterápico com ação neuroativa. A inibição da recaptação das monoaminas pode estar relacionada a uma alteração do gradiente iônico de Na+, através da estimulação da atividade da Na+,K+-ATPase, o que leva a crer que ULI possui um perfil de ação lamotrigina-like. Dessa forma, ULI torna-se um novo e promissor padrão molecular de substância com atividade no sistema nervoso central. / The aim of this work was to continue studying the antidepressant mechanism of Hypericum polyanthemum (POL) and its compound derived from phloroglucinols class uliginosin B (ULI). Considering the potential for development of new drugs with this plant, a preclinical study of toxicity with POL was accomplished, administering acute and repeated-doses in mice. The cyclo-hexane extract administration by oral route (p.o.) of POL (90 mg/kg) was able to significantly reduce the immobility time of rats and mice in the forced swimming test (FST). ULI (10 mg/kg, p.o.) also produced a reduction in immobility time in two models predictive of antidepressant activity in mice, FST and the tail suspension test (TST). Simultaneously administration (p.o) of subeffective doses of POL (45 mg/kg) and ULI (5 mg/kg) were able to potentiate the antidepressant effect of subeffective dose of imipramine (10 mg/kg), bupropion (3 mg/kg ) and fluoxetine (15 mg/kg), in the mouse FST. The pretreatment of mice, by i.p. route, with SCH 23390 (dopamine D1 receptor antagonist); sulpiride (dopamine D2 receptor antagonist); (α1 adrenoceptor antagonist); yohimbine (α2 adrenoceptor antagonist) and p-chlorophenylalanine methyl ester (pCPA- an inhibitor of serotonin (5-HT) synthesis) prevented anti- immobility effect of ULI in FST. In vitro, ULI inhibited synaptosomal uptake of dopamine ([3H]-DA), noradrenaline ([3H]-NA) and 5-HT ([3H]-5-HT), without binding with monoaminergic transporters, and this was demonstrated by different concentrations of ULI that did not affect the binding of [3H]-mazindol, [3H]-nisoxetine and [3H]-citalopram to DA, NA and 5-HT uptake sites, respectively. These results suggest that ULI has non-selective action on the monoaminergic system, which may represent a new compound with triple reuptake inhibition; furthermore, ULI has a mechanism of action different from the classical antidepressants by inhibiting monoamine reuptake without bind to respective neurotransporters. In addition we have performed a biochemical study for activity of Na+, K+-ATPase in cerebral cortex and hippocampus of mice. Acute and repeated oral treatment (3 days, 1 x per day) increased enzyme activity in cortex at different times. ULI did not alter Na+, K+- ATPase activity in hippocampus, and this result confirms the hypothesis that ULI can be contributing to the maintenance of neuronal excitability by stimulating this enzyme, and acting selectively in cerebral cortex. Moreover, we investigated the role of ULI on voltage-gated sodium channels (Na+), through pre-administration of veratrine ( Na+ channel oppener). Veratrine was able to abolish the antidepressant effect of ULI in TNF and this result indicates the possibility that ULI blocks the Na+ channels by altering the ionic gradient through the stimulation of Na+, K+-ATPase and impairing or inhibiting the reuptake of monoamines. In toxicity experiments, the more pronounced physiological, biochemical and histopathological changes were observed in mice that received POL at doses 5 and/or 10 fold higher than the effective dose in TNF. However, POL has chemically different from H. perforatum, suggesting low risk of this species in relation to phototoxicity (absence of hypericin). Considering all results, we supposed that POL could be a product with potential for the development of new drugs. The monoamine reuptake inhibition can be related to a change on the gradient of Na+ ion, by stimulation of Na+, K+-ATPase, which suggests that ULI has a lamotrigine-like profile. Therefore, we suggest that phloroglucinol derivative ULI represents a promising new molecular pattern with central nervous system activity.

O objetivo deste trabalho foi ampliar o estudo do mecanismo de ação antidepressivo de Hypericum polyanthemum (POL) e de seu composto derivado da classe dos floroglucinóis uliginosina B (ULI). Considerando o potencial desta planta para o desenvolvimento de novos fármacos, realizou-se um estudo pré-clínico de toxicidade aguda e doses repetidas de POL em camundongos. A administração via oral (v.o.) do extrato ciclo-hexano de POL (90 mg/kg) foi capaz de reduzir significativamente o tempo de imobilidade de ratos e camundongos no teste de natação forçada (TNF). A administração de ULI (10 mg/kg, v.o.) igualmente reduziu o tempo de imobilidade no TNF e também no teste de suspensão pela cauda (TSC). A administração simultânea (v.o), das subdoses de POL (45 mg/kg) e ULI (5 mg/kg) foram capazes de potencializar o efeito antidepressivo das subdoses de imipramina (10 mg/kg), bupropiona (3 mg/kg) e fluoxetina (15 mg/kg), no TNF em camundongos. O pré- tratamento de camundongos, pela via intraperitoneal, com SCH 23390 (antagonista de receptor dopaminérgico D1); sulpirida (antagonista de receptor dopaminérgico D2); prazosin (antagonista de receptor α1-adrenérgico); ioimbina (antagonista de receptor α2-adrenérgico) e p-clorofenilalanina metil éster (pCPA- inibidor da síntese de serotonina (5-HT), preveniu o efeito anti-imobilidade de ULI no TNF. In vitro, ULI inibiu a recaptação sinaptossomal de dopamina ([3H]-DA), noradrenalina ([3H]-NA) e serotonina ([3H]-5-HT), sem ligação aos transportadores, e isto foi demonstrado através das diferentes concentrações de ULI que não afetaram a ligação de [3H]- mazindol, [3H]-nisoxetina e [3H]-citalopram aos sítios de recaptação de DA, NA e 5- HT, respectivamente. Estes resultados sugerem que ULI tem ação não-seletiva sobre o sistema monoaminérgico, o que pode representar um novo composto com inibição tripla da recaptação; além disso possui mecanismo de ação diferente dos antidepressivos clássicos, inibindo a recaptação das monoaminas sem se ligar aos respectivos sítios específicos dos transportadores. Também realizou-se estudo bioquímico da atividade da Na+,K+-ATPase em córtex cerebral e hipocampo de camundongos. O tratamento agudo e repetido por via oral (3 dias, 1 x ao dia) aumentou a atividade desta enzima em córtex cerebral de camundongos em diferentes tempos. ULI não alterou a atividade da Na+,K+-ATPase em hipocampo dos camundongos, e esse resultado corrobora com a hipótese de que ULI pode estar contribuindo para a manutenção da excitabilidade neuronal estimulando esta enzima, e agindo seletivamente no córtex cerebral. Além disso, investigou-se o papel de ULI sobre os canais de sódio dependentes de voltagem (Na+), através da pré-administração de veratrina (ativador de canal de Na+). A veratrina bloqueou o efeito antidepressivo de ULI no TNF e este resultado indica a possibilidade de ULI estar bloqueando os canais de Na+ alterando o gradiente iônico através da estimulação da atividade da Na+,K+-ATPase e, prejudicando ou inibindo a recaptação das monoaminas. Nos experimentos de toxicidade, as mudanças fisiológicas, bioquímicas e histopatológicas mais pronunciadas foram observadas nos camundongos que receberam POL nas doses 5 e/ou 10 vezes maiores que a dose efetiva no TNF em camundongos. Entretanto, POL apresenta constituição química diferente de H. perforatum, sugerindo baixo risco desta espécie em relação à fototoxicidade (ausência de hipericina). Através dos dados obtidos neste estudo, acredita-se que POL pode se tornar uma espécie promissora no desenvolvimento de um novo fitoterápico com ação neuroativa. A inibição da recaptação das monoaminas pode estar relacionada a uma alteração do gradiente iônico de Na+, através da estimulação da atividade da Na+,K+-ATPase, o que leva a crer que ULI possui um perfil de ação lamotrigina-like. Dessa forma, ULI torna-se um novo e promissor padrão molecular de substância com atividade no sistema nervoso central. / The aim of this work was to continue studying the antidepressant mechanism of Hypericum polyanthemum (POL) and its compound derived from phloroglucinols class uliginosin B (ULI). Considering the potential for development of new drugs with this plant, a preclinical study of toxicity with POL was accomplished, administering acute and repeated-doses in mice. The cyclo-hexane extract administration by oral route (p.o.) of POL (90 mg/kg) was able to significantly reduce the immobility time of rats and mice in the forced swimming test (FST). ULI (10 mg/kg, p.o.) also produced a reduction in immobility time in two models predictive of antidepressant activity in mice, FST and the tail suspension test (TST). Simultaneously administration (p.o) of subeffective doses of POL (45 mg/kg) and ULI (5 mg/kg) were able to potentiate the antidepressant effect of subeffective dose of imipramine (10 mg/kg), bupropion (3 mg/kg ) and fluoxetine (15 mg/kg), in the mouse FST. The pretreatment of mice, by i.p. route, with SCH 23390 (dopamine D1 receptor antagonist); sulpiride (dopamine D2 receptor antagonist); (α1 adrenoceptor antagonist); yohimbine (α2 adrenoceptor antagonist) and p-chlorophenylalanine methyl ester (pCPA- an inhibitor of serotonin (5-HT) synthesis) prevented anti- immobility effect of ULI in FST. In vitro, ULI inhibited synaptosomal uptake of dopamine ([3H]-DA), noradrenaline ([3H]-NA) and 5-HT ([3H]-5-HT), without binding with monoaminergic transporters, and this was demonstrated by different concentrations of ULI that did not affect the binding of [3H]-mazindol, [3H]-nisoxetine and [3H]-citalopram to DA, NA and 5-HT uptake sites, respectively. These results suggest that ULI has non-selective action on the monoaminergic system, which may represent a new compound with triple reuptake inhibition; furthermore, ULI has a mechanism of action different from the classical antidepressants by inhibiting monoamine reuptake without bind to respective neurotransporters. In addition we have performed a biochemical study for activity of Na+, K+-ATPase in cerebral cortex and hippocampus of mice. Acute and repeated oral treatment (3 days, 1 x per day) increased enzyme activity in cortex at different times. ULI did not alter Na+, K+- ATPase activity in hippocampus, and this result confirms the hypothesis that ULI can be contributing to the maintenance of neuronal excitability by stimulating this enzyme, and acting selectively in cerebral cortex. Moreover, we investigated the role of ULI on voltage-gated sodium channels (Na+), through pre-administration of veratrine ( Na+ channel oppener). Veratrine was able to abolish the antidepressant effect of ULI in TNF and this result indicates the possibility that ULI blocks the Na+ channels by altering the ionic gradient through the stimulation of Na+, K+-ATPase and impairing or inhibiting the reuptake of monoamines. In toxicity experiments, the more pronounced physiological, biochemical and histopathological changes were observed in mice that received POL at doses 5 and/or 10 fold higher than the effective dose in TNF. However, POL has chemically different from H. perforatum, suggesting low risk of this species in relation to phototoxicity (absence of hypericin). Considering all results, we supposed that POL could be a product with potential for the development of new drugs. The monoamine reuptake inhibition can be related to a change on the gradient of Na+ ion, by stimulation of Na+, K+-ATPase, which suggests that ULI has a lamotrigine-like profile. Therefore, we suggest that phloroglucinol derivative ULI represents a promising new molecular pattern with central nervous system activity.

Le Trouble de Stress Post-Traumatique (TSPT) est une pathologie qui se développe chez des sujets exposés à des événements traumatiques. Cette pathologie est caractérisée par des reviviscences du traumatisme induisant des troubles anxieux invalidants et durables. Ces reviviscences, provoquées par des indices de rappel, sont à l'origine des fréquentes rechutes qui caractérisent le TSPT. La dépendance aux drogues d'abus est également caractérisée par une hyperréactivité aux indices de rappel qui est responsable du désir irrépressible de drogue ou " craving " et des nombreuses rechutes après abstinence. Nous avons fait l'hypothèse que cette susceptibilité aux indices environnementaux, commune aux deux pathologies, pourrait être due à un découplage des systèmes monoaminergiques induit par l'exposition à des conditions intenses, drogues d'abus ou traumatisme. Les données de cette thèse montrent que notre modèle animal de traumatisme (le Single Prolonged Stress) reproduit chez les individus vulnérables les symptômes de la pathologie, et une réactivité aux indices de rappel. Nos données indiquent également qu'un traumatisme induit, chez les individus vulnérables, une désensibilisation comportementale et une sensibilisation noradrénergique corticale, supportant l'hypothèse de découplage monoaminergique. Enfin, nous avons développé une nouvelle approche thérapeutique, le " remodelage émotionnel " capable de diminuer durablement les symptômes de type TSPT. Les résultats obtenus dans cette thèse, soutiennent l'hypothèse de bases physiologiques communes entre le TSPT et l'addiction, et proposent de nouvelles approches thérapeutiques pour ces deux pathologies. / Post-Traumatic Stress disorder (PSTD) appears on a part of individuals exposed to traumatic events. This pathology is characterized by frequent re-experiencing of the traumatic event inducing disabling and long-lasting anxiety disorders. These flashbacks, triggered by reminder cues, are responsible for the frequent relapses that characterize PTSD. Addiction to drugs of abuse is also characterized by a hyper reactivity to reminder cues which is responsible for drug craving and relapses. We hypothesized that such a susceptibility to environmental cues, common to both pathologies, could be due to an uncoupling of monoaminergic systems induced by exposure to intense conditions (trauma or drugs). Data from this thesis showed that our animal model of PTSD (the Single Prolonged Stress) reproduced PTSD-like symptoms on vulnerable rats, and reactivity to reminder cues. Our data also showed that trauma induced a behavioral desensitization and a cortical noradrenergic sensitization, in vulnerable traumatized rats, supporting the hypothesis of monoaminergic uncoupling. Finally, we developed a new therapeutic approach, the "emotional remodeling" which was shown to durably decrease PTSD-like symptoms. The results obtained in this thesis support the hypothesis of common physiological basis between PTSD and drug addiction, and offer new therapeutic approaches for these two pathologies.

Fluoxetine and escitalopram are the only antidepressants approved by the Food and Drug Administration of the United States of America (FDA) for treatment of major depression in children and adolescents. Both drugs are selective serotonin reuptake inhibitors (SSRIs). In recent years there has been a growing concern over the long-term developmental effects of early-life exposure to SSRIs. The current study employed male Flinders Sensitive Line (FSL) rats, a well described and validated translational model of depression, to investigate the long term effects of pre-pubertal fluoxetine exposure. First we examined the effect of such early-life exposure on the development of depressive-like behaviour, locomotor activity and anxiety-like behaviour as manifested in early adulthood. Next, the current study investigated the effect of pre-pubertal fluoxetine exposure on the acute monoaminergic stress response, as displayed later in life. Animals received either saline (vehicle control), or 10 mg/kg/day fluoxetine from postnatal day (ND+) 21 to ND+34 (pre-puberty). The treatment period was chosen to coincide with a developmental phase where the serotonergic system’s neurodevelopment had been completed, yet the noradrenergic and dopaminergic systems had not, a scenario comparable to neurodevelopment in human adolescents. Both behavioural and in vivo intra-cerebral microdialysis experiments were conducted after ND+60 (early adulthood). On ND+60 rats allocated to behavioural experiments were evaluated for depressive-like behaviour in the forced swim test (FST), locomotor activity in the open field test (OFT), and anxiety-like behaviour in the OFT. Corticosterone concentrations were shown to be significantly higher in male FSL rats exposed to a 10 minute forced swim stress when compared to male FSL rats not exposed to a forced swim stress on ND+60. In the microdialysis experiments the rats were exposed to an acute 10 minute forced swim stress and the concentrations of the monoamines and their metabolites were measured before, during, and after the acute stressor. Relative to saline-treated (control) rats, fluoxetine-treated FSL rats did not show long-term changes in immobility in the FST (i.e. no anti-depressant-like activity) on ND+60. Like-wise anxiety-like behaviour in the OFT did not change. However, a significant decrease in locomotor activity was observed in fluoxetine-treated FSL rats compared to saline-treated (control) rats. These data suggest that a long-lasting anti-depressant-like effect of fluoxetine may be masked by the effect on locomotor activity. With measurements from the microdialysis experiments a significant attenuation of the noradrenergic stress response was observed in fluoxetine-treated rats compared to saline controls. A similar picture was observed for 5-hydroxyindole-3-acetic acid (5-HIAA), a metabolite of serotonin (5-HT), although the latter was not statistically significant. At baseline, before the stressor, significant increase in dopamine (DA) levels were observed in fluoxetine treated rats when compared to saline controls, suggesting that enhanced dopamine neurotransmission may comprise a long-term effect of pre-pubertal fluoxetine treatment. There were no discernible differences in homovanilllic acid (HVA) concentrations between fluoxetine-treated rats and saline controls. In conclusion significant developmental effects of pre-pubertal fluoxetine exposure were observed later in life and these findings warrant further investigation. / MPharm (Pharmacology), North-West University, Potchefstroom Campus, 2015

Fluoxetine and escitalopram are the only antidepressants approved by the Food and Drug Administration of the United States of America (FDA) for treatment of major depression in children and adolescents. Both drugs are selective serotonin reuptake inhibitors (SSRIs). In recent years there has been a growing concern over the long-term developmental effects of early-life exposure to SSRIs. The current study employed male Flinders Sensitive Line (FSL) rats, a well described and validated translational model of depression, to investigate the long term effects of pre-pubertal fluoxetine exposure. First we examined the effect of such early-life exposure on the development of depressive-like behaviour, locomotor activity and anxiety-like behaviour as manifested in early adulthood. Next, the current study investigated the effect of pre-pubertal fluoxetine exposure on the acute monoaminergic stress response, as displayed later in life. Animals received either saline (vehicle control), or 10 mg/kg/day fluoxetine from postnatal day (ND+) 21 to ND+34 (pre-puberty). The treatment period was chosen to coincide with a developmental phase where the serotonergic system’s neurodevelopment had been completed, yet the noradrenergic and dopaminergic systems had not, a scenario comparable to neurodevelopment in human adolescents. Both behavioural and in vivo intra-cerebral microdialysis experiments were conducted after ND+60 (early adulthood). On ND+60 rats allocated to behavioural experiments were evaluated for depressive-like behaviour in the forced swim test (FST), locomotor activity in the open field test (OFT), and anxiety-like behaviour in the OFT. Corticosterone concentrations were shown to be significantly higher in male FSL rats exposed to a 10 minute forced swim stress when compared to male FSL rats not exposed to a forced swim stress on ND+60. In the microdialysis experiments the rats were exposed to an acute 10 minute forced swim stress and the concentrations of the monoamines and their metabolites were measured before, during, and after the acute stressor. Relative to saline-treated (control) rats, fluoxetine-treated FSL rats did not show long-term changes in immobility in the FST (i.e. no anti-depressant-like activity) on ND+60. Like-wise anxiety-like behaviour in the OFT did not change. However, a significant decrease in locomotor activity was observed in fluoxetine-treated FSL rats compared to saline-treated (control) rats. These data suggest that a long-lasting anti-depressant-like effect of fluoxetine may be masked by the effect on locomotor activity. With measurements from the microdialysis experiments a significant attenuation of the noradrenergic stress response was observed in fluoxetine-treated rats compared to saline controls. A similar picture was observed for 5-hydroxyindole-3-acetic acid (5-HIAA), a metabolite of serotonin (5-HT), although the latter was not statistically significant. At baseline, before the stressor, significant increase in dopamine (DA) levels were observed in fluoxetine treated rats when compared to saline controls, suggesting that enhanced dopamine neurotransmission may comprise a long-term effect of pre-pubertal fluoxetine treatment. There were no discernible differences in homovanilllic acid (HVA) concentrations between fluoxetine-treated rats and saline controls. In conclusion significant developmental effects of pre-pubertal fluoxetine exposure were observed later in life and these findings warrant further investigation. / MPharm (Pharmacology), North-West University, Potchefstroom Campus, 2015