A epilepsia do lobo temporal causada por esclerose hipocampal é a epilepsia farmacorresistente mais frequente em adultos. Os transtornos de humor são a comorbidade psiquiátrica mais comuns nesses pacientes. Os mecanismos fisiopatológicos comuns entre a epilepsia e as comorbidades psiquiátricas incluem alterações na via serotoninérgica. Os polimorfismos de genes relacionados à via serotoninérgica (receptores, monoamino oxidase A, transportador de serotonina) podem estar relacionadas à coexistência destas condições. O objetivo principal deste estudo foi o de determinar a possível associação entre os polimorfismos dos genes que codificam os receptores de serotonina 5HT1A (rs6295), 5HT1B (rs6296), e 5HT2C(rs6318); a monoamino oxidase A (MAOA-uVNTR); e o transportador de serotonina (5-HTTLPR e 5-HTTVNTR) e a presença de depressão nesses pacientes, em comparação à pacientes sem epilepsia com depressão, voluntários saudáveis sem epilepsia e sem transtornos psiquiátricos. O objetivo secundário foi o de avaliar a possível associação entre essas variantes genéticas e a susceptibilidade ao desenvolvimento de crises epilépticas assim como sua influência sobre as características clínicas da epilepsia. Foram avaliados 119 pacientes com epilepsia do lobo temporal causada por esclerose hipocampal com (56 pacientes) e sem (63 pacientes) depressão; 146 pacientes com transtorno depressivo maior, sem características psicóticas e 113 controles saudáveis. Os indivíduos foram genotipados para os polimorfismos rs6295, rs6296, rs6318, MAOA-uVNTR, 5-HTTLPR e 5-HTTVNTR. Em relação ao polimorfismo rs6295, não houve diferença na distribuição dos genótipos entre epilepsia e depressão sem epilepsia (p = 1.000) e epilepsia e controles (p = 1.000). Não foi observada diferença entre o polimorfismo rs6296 e os grupos epilepsia e depressão sem epilepsia (p = 0,838) e epilepsia e controles (p = 0,838). Não houve diferença entre o polimorfismo rs6318 e os grupos epilepsia e depressão sem epilepsia (p = 0,207) e epilepsia e controles (p = 0,296). Não foi observada diferença entre o polimorfismo MAOA-uVNTR e os grupos epilepsia e depressão (p = 0,799) e epilepsia e controles (p = 1,000). Não houve diferença entre o polimorfismo 5-HTTLPR e os grupos epilepsia e depressão sem epilepsia (p = 1.000) e epilepsia e controles (p = 0,626). Não foi observada diferença entre o polimorfismo 5-HTTVNTR e epilepsia e depressão sem epilepsia (p = 1.000) e epilepsia e controles (p = 0.790). No grupo de pacientes com epilepsia, não houve diferença entre os polimorfismos estudados e a presença de depressão. Foi observada correlação entre alelos de alta atividade transcricional em homozigose ou hemizigose (3,5 e 4 repetições) do polimorfismo MAOA-uVNTR e ocorrência de crises epilépticas diárias/semanais (p=0,032) e crises tônico-clônicas bilaterais (p=0,016). Também houve relação entre o alelo de 12 repetições em homozigose (alelo relacionados a maior produção de RNA mensageiro) do polimorfismo 5-HTTVNTR e história familiar de epilepsia nos pacientes com epilepsia (p=0,013). Alelos de alta atividade transcricional do polimorfismo MAOA-uVNTR estão relacionados a maior eficiência transcricional do gene da monoamino oxidase A e maior atividade enzimática, levando a aumento na metabolização da serotonina. Portanto, é possível que a redução na concentração de serotonina possa levar a um aumento na hiperexcitabilidade neuronal, tendo como consequência um aumento na frequência de crises e ocorrência de crises tônico-clônicas bilaterais. O alelo de 12 repetições do 5-HTTVNTR relaciona-se a maior produção de RNA mensageiro, levando a maior eficiência transcricional do gene do 5-HTTVNTR. Este achado sugere a presença de um subgrupo de pacientes com predisposição familiar para a ocorrência de crises epilépticas devido a um estado de hiperexcitabilidade neuronal determinado pela maior expressão do transportador de serotonina. Este estudo sugere que os polimorfismos avaliados não estão relacionados com a presença de epilepsia ou de comorbidades psiquiátricas nesses pacientes, mas sim com aspectos clínicos da epilepsia (frequência de crises epilépticas, presença de crises tônico-clônicas bilaterais e história familiar de epilepsia) nos pacientes com epilepsia do lobo temporal causada por esclerose hipocampal / Temporal lobe epilepsy caused by hippocampal sclerosis is the most common drug-resistant epilepsy in adults. Mood disorders are the most common psychiatric comorbidity in these patients. Common pathophysiological mechanisms between epilepsy and psychiatric comorbidities include changes in the serotonergic pathway. Polymorphisms of genes related to the serotoninergic pathway (receptors, monoamine oxidase A, serotonin transporter) may be associated with the coexistence of these conditions. The primary objective of this study was to determine the possible association between polymorphisms of the genes encoding serotonin 5HT1A receptors (rs6295), 5HT1B (rs6296), and 5HT2C (rs6318); monoamine oxidase A (MAOA-uVNTR); and the serotonin transporter (5-HTTLPR and 5-HTTVNTR) and the presence of depression in these patients compared to patients without epilepsy with depression, and healthy volunteers without epilepsy and psychiatric disorders. The secondary objective was to evaluate the possible association between these variants and the susceptibility to the development of epileptic seizures and their influence on the clinical characteristics of epilepsy. We evaluated 119 patients with temporal lobe epilepsy caused by hippocampal sclerosis with (56 patients) and without (63 patients) depression, 146 patients with major depressive disorder, without psychotic characteristics, and 113 healthy controls. The individuals were genotyped for polymorphisms rs6295, rs6296, rs6318, MAOA-uVNTR, 5-HTTLPR and 5-HTTVNTR. Regarding the rs6295 polymorphism, no difference was observed in the distribution of genotypes between epilepsy and depression without epilepsy groups (p = 1,000) and epilepsy and controls (p = 1,000). No difference was observed for the rs6296 polymorphism between epilepsy and depression without epilepsy groups (p = 0.838) and epilepsy and controls (p = 0.838). There was no difference for the rs6318 polymorphism between epilepsy and depression without epilepsy groups (p = 0.207) and epilepsy and controls (p = 0.296). No difference was observed for the MAOA-uVNTR polymorphism between epilepsy and depression without epilepsy groups (p = 0.799) and epilepsy and controls (p = 1,000). There was no difference between the polymorphism 5-HTTLPR and epilepsy and depression groups without epilepsy (p = 1,000) and epilepsy and controls (p = 0.626). No difference was observed between the 5-HTTVNTR polymorphism and epilepsy and depression without epilepsy groups (p = 1,000) and epilepsy and controls (p = 0.790). In the group of patients with epilepsy, there was no difference between the polymorphisms studied and the history of psychiatric comorbidities. A correlation was observed between alleles with high transcriptional activity in homozygosis or hemizygosis (3.5 and 4 repeats) of the MAOA-uVNTR polymorphism and occurrence of daily /weekly epileptic seizures (p = 0.032) and bilateral tonic-clonic seizures (p = 0.016). There was also a relationship between the allele of 12 repeats in homozygosis (allele related to higher messenger RNA production) of the 5-HTTVNTR polymorphism and family history of epilepsy in patients with epilepsy (p = 0.013). High transcriptional activity alleles of MAOA-uVNTR are related to the higher transcriptional efficiency of the monoamine oxidase A gene and higher enzymatic activity, leading to increased serotonin metabolism. Therefore, it is possible that the reduction in serotonin concentration may lead to an increase in neuronal hyperexcitability, increasing the frequency of seizures and occurrence of bilateral tonic-clonic seizures. The 12-repeat allele of 5-HTTVNTR is related to increased messenger RNA production, leading to increased transcriptional efficiency of the 5-HTTVNTR gene. This finding suggests the presence of a subgroup of patients with a familial predisposition for the occurrence of epileptic seizures due to a state of neuronal hyperexcitability determined by the higher expression of the serotonin transporter. This study suggests that the polymorphisms evaluated are not related to the presence of epilepsy or psychiatric comorbidities in these patients, but rather to clinical aspects of epilepsy (frequency of epileptic seizures, the presence of bilateral tonic-clonic seizures, and family history of epilepsy) in patients with temporal lobe epilepsy and hippocampal sclerosis

Die Honigbiene <i>Apis mellifera</i> gilt seit langem als Modell-Organismus zur Untersuchung von Lern- und Gedächtnisvorgängen sowie zum Studium des Sozialverhaltens und der Arbeitsteilung. Bei der Steuerung und Regulation dieser Verhaltensweisen spielt das Indolalkylamin Serotonin eine wesentliche Rolle. Serotonin entfaltet seine Wirkung durch die Bindung an G-Protein-gekoppelte Rezeptoren (GPCRs). In der vorliegenden Arbeit wird der erste Serotonin-Rezeptor aus der Honigbiene molekular charakterisiert. <br><br> Durch die Anwendung zwei verschiedener Klonierungsstrategien konnten drei cDNA-Sequenzen isoliert werden, die für potentielle Serotonin-Rezeptoren kodieren. Die Sequenzen weisen die größte Ähnlichkeit zu dem 5-HT7- und 5-HT2-Rezeptor von Drosophila melanogaster bzw. dem 5-HT1-Rezeptor von <i>Panulirus interruptus</i> auf. Die isolierten Serotonin-Rezeptoren der Honigbiene wurden dementsprechend Am(<i>Apis mellifera</i>)5-HT1, Am5-HT2 und Am5-HT7 benannt. <br><br> Das Hydropathieprofil des Am5-HT1-, Am5-HT2- und Am5-HT7-Rezeptors deutet auf das Vorhandensein des charakteristischen heptahelikalen Aufbaus G-Protein-gekoppelter Rezeptoren hin. Die abgeleiteten Aminosäuresequenzen zeigen typische Merkmale biogener Amin-Rezeptoren. Aminosäuren, die eine Bedeutung bei der Bildung der Liganden-Bindungstasche, der Rezeptor-Aktivierung und der Kopplung eines G-Proteins an den Rezeptor haben, sind in allen drei Rezeptoren konserviert. Interessanterweise ist jedoch das in den meisten biogenen Amin-Rezeptoren vorhandene DRY-Motiv in dem Am5-HT2- und Am5-HT7-Rezeptor nicht konserviert. Das Vorhandensein einer PDZ-Domäne in dem Am5-HT1- und Am5-HT7-Rezeptor lässt vermuten, dass diese Rezeptoren als Adapterproteine fungieren, die Signalmoleküle zu einem Signaltransduktionskomplex vereinigen. <br><br> RT-PCR-Experimente zeigen die Expression der Rezeptoren in verschiedenen Geweben der Honigbiene. Auffallend ist die hohe Expression im Zentralgehirn. Des Weiteren konnte die Expression der Serotonin-Rezeptoren in den optischen Loben, Antennalloben sowie in der Peripherie, d.h. in der Flugmuskulatur und den Malpighischen Gefäßen nachgewiesen werden. Durch in situ Hybridisierungen wurde die Expression in Gefrierschnitten von Gehirnen adulter Sammlerinnen im Detail untersucht. Transkripte der Rezeptoren sind in den Somata von intrinsischen Pilzkörperzellen, Neuronen der optischen Loben und Neuronen der Antennalloben vorhanden. <br><br> In einem heterologen Expressionssystem wurde der intrazelluläre Signalweg des Am5-HT7-Rezeptors untersucht. Die Aktivierung des stabil exprimierten Rezeptors durch Serotonin führt zur Bildung von cAMP. Der 5-HT7-Rezeptor spezifische Agonist 5-CT zeigt eine mit Serotonin vergleichbare Fähigkeit, die intrazelluläre cAMP-Konzentration zu erhöhen. Am5-HT7 gehört daher funktionell zu der Gruppe der 5-HT7-Rezeptoren. Der EC50-Wert von 1,06~nM (5-HT), ist im Vergleich zu anderen 5-HT7-Rezeptoren äußert niedrig. Des Weiteren wurde gezeigt, dass das basale cAMP-Niveau in den transfizierten Zellen im Vergleich zu nicht transfizierten Zellen deutlich erhöht ist. Das heißt, dass der Rezeptor auch in der Abwesenheit eines Liganden aktiv ist. Diese konstitutive Aktivität ist auch von anderen biogenen Amin-Rezeptoren bekannt. Methiothepin wurde als wirksamer inverser Agonist des Am5-HT7-Rezeptors identifiziert, da es in der Lage ist, der konstitutiven Aktivität entgegenzuwirken.<br><br> Die Ergebnisse der vorliegenden Arbeit deuten darauf hin, dass die Serotonin-Rezeptoren in verschiedenen Regionen des ZNS der Honigbiene an der Informationsverarbeitung beteiligt sind. Es kann eine Beeinflussung von Lern- und Gedächtnisprozessen sowie des olfaktorischen und visuellen Systems durch diese Rezeptoren vermutet werden. Mit der Klonierung und funktionellen Charakterisierung des ersten Serotonin-Rezeptors der Honigbiene ist eine Grundlage für die Untersuchung der molekularen Mechanismen der serotonergen Signaltransduktion geschaffen worden. / The honeybee <i>Apis mellifera</i> is a model organism for studying insect division of labor, learning and memory. An important substance that has been implicated in the control and regulation of these phenomena is the indolalkylamine serotonin (5-hydroxytryptamine, 5-HT) Pharmacological and functional studies indicate, that serotonin activates various receptor subtypes which predominantly belong to the family of G protein-coupled receptors (GPCRs).<br><br> Using a homology based screening approach on a brain-specific cDNA library of the honeybee and a PCR-based strategy we have isolated cDNAs encoding three putative serotonin receptors. The deduced amino acid sequences of these putative honeybee serotonin receptors show the highest homology to a 5-HT7 and a 5-HT2 receptor from <i>Drosophila melanogaster</i> and a 5-HT1 receptor from <i>Panulirus interruptus</i>, respectively. We have studied the distribution of the respective 5-HT receptor mRNAs in several tissues of the honeybee by RT-PCR. The analysis revealed a high amount in the central brain. By using in situ-hybridization we detected receptor encoding mRNA in cryostat sections of honeybee brain. We could prove receptor transcripts in neurons of the optic lobes, intrinsic mushroom body neurons, and deutocerebral neurons. <br><br> In a HEK 293 cell line, stably expressing the 5-HT7 receptor protein, we investigated the intracellular signalling pathway. When activated by serotonin, the heterologous expressed 5-HT7 receptor induces an increase in intracellular cAMP levels ([cAMP]i). The stimulation with other biogenic amines (octopamine, tyramine, and dopamine) did not induce a significant change in [cAMP]i Furthermore, Am5-HT7 causes a significant increase in the non-agonist stimulated cAMP levels relative to those of non-transfected cells. Therefore, the Am5-HT7 receptor displays agonist-independent (constitutive) activity which has also been demonstrated for many other GPCRs. <br><br> A specific affinity-purified anti-Am5-HT7 antibody detected a protein band of the expected size of ~66 kDa in homogenates of honeybee brains and HEK 293 cells expressing the Am5-HT7 receptor.

The mechanisms by which antipsychotics (neuroleptics) produce their therapeutic effects in schizophrenia are largely unknown. Although neuroleptic efficacy is attributed to central dopamine D2 and/or serotonin 5-HT2 receptor antagonism, clinical improvements in schizophrenia are not seen until two or three weeks after daily neuroleptic administration. The mechanisms underlying the neuroleptic response must therefore occur downstream from initial receptor blockade and be a consequence of chronic neurotransmitter receptor blockade. The goal of the present study was to use neuroleptics with varied dopamine vs. serotonergic receptor blocking profiles to elucidate some of these intracellular post receptor mechanisms. Since the final steps of both dopamine and serotonin synthesis require the enzyme aromatic L-amino acid decarboxylase (AADC), the effects of neuroleptics on AADC gene (mRNA) expression were examined in PC12 cells and compared to their effects on the synthetic enzyme tyrosine hydroxylase (TH) and ' c-fos' (an early immediate gene [IEG]) mRNA. The neuroleptics examined did not significantly regulate AADC mRNA in PC12 cells, and only haloperidol upregulated TH and 'c-fos' mRNA. Later studies in rats showed that acute neuroleptic administration increased ' c-fos' mRNA, whereas the immunoreactivity of a related IEG (delta FosB) was increased upon chronic treatment. These studies and a subsequent dose response study demonstrated that upregulation of both 'c-fos' mRNA and delta FosB immunoreactivity was most prominent in dopaminergic projection areas including the striatum and nucleus accumbens. Because it has been suggested that neuroleptic treatment might prevent neurodegeneration in schizophrenia, the effects of neuroleptics on the mRNA expression of neuroprotective target genes of delta FosB were examined both ' in vivo' and 'in vitro'. These genes included brain-derived neurotrophic factor (BDNF), the neuroprotective enzyme superoxide dismutase (SOD), and the low affinity nerve growth factor receptor (p75). While dopamine D2 blockade unfavorably regulated BDNF and p75 mRNA, 5-HT 2 blockade either had no effect on or favorably regulated BDNF, SOD, and p75 mRNA. Thus, although little about the contribution of serotonergic blockade in the neuroleptic response was determined, dopaminergic blockade regulated IEG's and several of their target genes. Future studies will be needed to understand the role of 5-HT2 receptor blockade in the neuroleptic response.

No description available.

Suicidal behavior has to be considered as a multifactorial phenomenon, which can be analyzed in a classifying-phenomenological manner. We have examined the relation of parasuicide typology to whole blood concentrations of serotonin, HVA, and tryptophan in 58 patients classified into 4 groups of parasuicide typology compared to 22 nonsuicidal depressed patients and 20 healthy subjects. Suicidal patients classified as impetuous, desperate and ambivalent types had significantly reduced whole blood 5-HT levels in comparison with the appealing type as well as nonsuicidal subjects. No differences were detected in the HVA content, but whole blood tryptophan concentrations were significantly reduced in impetuous suicidal patients and depressed patients compared to healthy subjects. This study provides evidence for reduced whole blood serotonin content based on different types of parasuicide. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

Diss. (sammanfattning) Uppsala : Univ., 2002. / Härtill 5 uppsatser.

Doenças e comportamentos de risco relacionados ao polimorfismo T102C do gene 5- HT2A, como esquizofrenia, suicídio, impulsividade, alcoolismo, tabagismo, entre outros, podem encurtar o tempo de vida médio. Uma amostra de 687 indivíduos residentes na região metropolitana da Grande Porto Alegre foi genotipada e categorizada de acordo com suas respectivas idades e gêneros. Foram observadas diferenças significativas entre a distribuição dos genótipos do polimorfismo T102C do gene 5-HT2A e idade média da amostra (p=0,026) e também entre os genótipos e grupos etários (p=0,012). Estes resultados sugerem que o polimorfismo T102C do gene 5-HT2A possa desempenhar algum papel no tempo de vida médio dos seres humanos. / Diseases and risk behaviors related to the T102C polymorphism of the 5-HT2A gene such as schizophrenia, suicide, impulsivity, alcoholism, smoking addiction, among others, may potentially shorten mean life span. A sample of 687 individuals residents in Porto Alegre metropolitan region was genotyped and categorized according to their respective age and gender. Significant differences were found between the distribution of genotypes of T102C polymorphism of gene 5-HT2A and the mean age of the sample (p=0.026) as well as distribution of genotypes and age groups (p=0.012). The present results suggest that T102C polymorphism of gene 5-HT2A may play a role in mean life span of human beings.

Doenças e comportamentos de risco relacionados ao polimorfismo T102C do gene 5- HT2A, como esquizofrenia, suicídio, impulsividade, alcoolismo, tabagismo, entre outros, podem encurtar o tempo de vida médio. Uma amostra de 687 indivíduos residentes na região metropolitana da Grande Porto Alegre foi genotipada e categorizada de acordo com suas respectivas idades e gêneros. Foram observadas diferenças significativas entre a distribuição dos genótipos do polimorfismo T102C do gene 5-HT2A e idade média da amostra (p=0,026) e também entre os genótipos e grupos etários (p=0,012). Estes resultados sugerem que o polimorfismo T102C do gene 5-HT2A possa desempenhar algum papel no tempo de vida médio dos seres humanos. / Diseases and risk behaviors related to the T102C polymorphism of the 5-HT2A gene such as schizophrenia, suicide, impulsivity, alcoholism, smoking addiction, among others, may potentially shorten mean life span. A sample of 687 individuals residents in Porto Alegre metropolitan region was genotyped and categorized according to their respective age and gender. Significant differences were found between the distribution of genotypes of T102C polymorphism of gene 5-HT2A and the mean age of the sample (p=0.026) as well as distribution of genotypes and age groups (p=0.012). The present results suggest that T102C polymorphism of gene 5-HT2A may play a role in mean life span of human beings.

Doenças e comportamentos de risco relacionados ao polimorfismo T102C do gene 5- HT2A, como esquizofrenia, suicídio, impulsividade, alcoolismo, tabagismo, entre outros, podem encurtar o tempo de vida médio. Uma amostra de 687 indivíduos residentes na região metropolitana da Grande Porto Alegre foi genotipada e categorizada de acordo com suas respectivas idades e gêneros. Foram observadas diferenças significativas entre a distribuição dos genótipos do polimorfismo T102C do gene 5-HT2A e idade média da amostra (p=0,026) e também entre os genótipos e grupos etários (p=0,012). Estes resultados sugerem que o polimorfismo T102C do gene 5-HT2A possa desempenhar algum papel no tempo de vida médio dos seres humanos. / Diseases and risk behaviors related to the T102C polymorphism of the 5-HT2A gene such as schizophrenia, suicide, impulsivity, alcoholism, smoking addiction, among others, may potentially shorten mean life span. A sample of 687 individuals residents in Porto Alegre metropolitan region was genotyped and categorized according to their respective age and gender. Significant differences were found between the distribution of genotypes of T102C polymorphism of gene 5-HT2A and the mean age of the sample (p=0.026) as well as distribution of genotypes and age groups (p=0.012). The present results suggest that T102C polymorphism of gene 5-HT2A may play a role in mean life span of human beings.

Neonatal 6-hydroxydopamine (6-OHDA) treatment of rats is associated with concurrent supersensitization of dopamine (DA) D1 and serotonin 5-HT1C receptors, for agonist-induced oral activity. The present study was conducted to determine if graded reduction of striatal DA content and/or graded elevation of striatal 5-HT content by 6-OHDA would alter sensitivity of either receptor type, and thereby influence oral activity responses to DA and 5-HT agonists. At 3 days after birth, groups of rats were pretreated with desipramine (20 mg/kg i.p.), 1 h before administration of a range of doses of 6-OHDA HBr (15, 30, 60, 100, 150 and 200 μg, i.c.v., salt form; half in each lateral ventricle) or the vehicle, saline (0.85%)-ascorbic acid (0.1%). Between 2 and 4 months, a series of challenge doses of SKF 38393 HCl (0.30 to 3.0 mg/kg i.p.) and m-chlorophenylpiperazine 2HCl (0.30 to 6.0 mg/kg i.p.; m-CPP 2HCl) were administered to each group of rats and oral activity was observed. Oral activity was determined for 1 min every 10 min during a 60-min period, starting 10 min after injection of agonist or vehicle. SKF 38393 dose-response curves demonstrated enhanced oral activity responses in rats lesioned neonatally with 150 or 200 μg of 6-OHDA. m-CPP dose-response curves demonstrated enhanced oral activity responses in these 2 groups of rats, as well as those lesioned neonatally with 100 μg of 6-OHDA. Striatal DA content was reduced by > 97% in these 3 groups of rats. Striatal 5-HT content was elevated by > 80% in rats treated neonatally with 150- or 200-μg doses of 6-OHDA, and by 50% in rats treated neonatally with the 100-μg dose of 6-OHDA. Lower doses of 6-OHDA produced less of an effect on striatal DA and 5-HT content. Regression analysis determined that both SKF 38393- and m-CPP-induced oral activities were most closely correlated with the magnitude of change in striatal content of DA. These findings demonstrate that 5-HT agonist responses can be enhanced when DA agonist responses are not enhanced. Also, in neonatal 6-OHDA-lesioned rats the extent of DA depletion vs. the extent of 5-HT elevation seems to be a critical factor in the enhanced behavioral effects of DA and 5-HT agonists.