No description available.

No description available.

<p>While constituting a well functioning interface with the aqueous environment in utero, the skin offers a poor barrier after very preterm birth. As a result, transepidermal water loss (TEWL) is high, a fact which has important clinical consequences in these infants. To investigate the transport of water through perinatal skin and the potential role of aquaporin (AQP), a water channel protein, in this process, we determined TEWL in a group of extremely preterm infants, and in an experimental rat model we analyzed the expression and distribution of AQP in perinatal skin in relation to TEWL, skin surface hydration and water content. The effects of antenatal corticosteroids (ANS) and of restricted intake of fluids and nutrients on barrier characteristics of the perinatal skin and its AQP expression were also studied.</p><p>In infants born at 24 and 25 weeks of gestation TEWL was very high in the first days after birth and decreased with increasing postnatal age. At a postnatal age of 4 weeks, TEWL was still twice as high as previously reported in infants born at a gestational age of 25-27 weeks and four times higher than in infants born at term. In the rat model, immunohistochemical analysis revealed that AQP1 and AQP3 are abundantly expressed in the skin. AQP1 was expressed exclusively in dermal capillaries and AQP3 in basal layers of the epidermis. AQP1 and AQP3 mRNA as assessed by semiquantitative RT-PCR was higher in fetal than in adult skin. As in infants, TEWL and skin surface hydration were inversely related to gestational age in the rat. In preterm rat pups exposed to ANS, TEWL and skin surface hydration were lower than in unexposed controls, and AQP3 expression was selectively induced by ANS. In term newborn rat pups, restriction of fluid and nutrient intake resulted in a higher skin water content and higher TEWL early after birth, while at an age of 7 days TEWL was lower in fasting rat pups than in controls, although skin water content was still higher.</p><p>To conclude, TEWL is very high in extremely preterm infants early after birth and then decreases at a slower rate than previously reported for a group of slightly more mature infants. </p><p>This is the first time that the distribution and gene expression of AQP1 and AQP3 have been demonstrated in perinatal skin. The localization and expression of AQP in the skin might indicate that these water channels are involved in the regulation of skin hydration and transepidermal water transport in the fetus and newborn infant.</p>

While constituting a well functioning interface with the aqueous environment in utero, the skin offers a poor barrier after very preterm birth. As a result, transepidermal water loss (TEWL) is high, a fact which has important clinical consequences in these infants. To investigate the transport of water through perinatal skin and the potential role of aquaporin (AQP), a water channel protein, in this process, we determined TEWL in a group of extremely preterm infants, and in an experimental rat model we analyzed the expression and distribution of AQP in perinatal skin in relation to TEWL, skin surface hydration and water content. The effects of antenatal corticosteroids (ANS) and of restricted intake of fluids and nutrients on barrier characteristics of the perinatal skin and its AQP expression were also studied. In infants born at 24 and 25 weeks of gestation TEWL was very high in the first days after birth and decreased with increasing postnatal age. At a postnatal age of 4 weeks, TEWL was still twice as high as previously reported in infants born at a gestational age of 25-27 weeks and four times higher than in infants born at term. In the rat model, immunohistochemical analysis revealed that AQP1 and AQP3 are abundantly expressed in the skin. AQP1 was expressed exclusively in dermal capillaries and AQP3 in basal layers of the epidermis. AQP1 and AQP3 mRNA as assessed by semiquantitative RT-PCR was higher in fetal than in adult skin. As in infants, TEWL and skin surface hydration were inversely related to gestational age in the rat. In preterm rat pups exposed to ANS, TEWL and skin surface hydration were lower than in unexposed controls, and AQP3 expression was selectively induced by ANS. In term newborn rat pups, restriction of fluid and nutrient intake resulted in a higher skin water content and higher TEWL early after birth, while at an age of 7 days TEWL was lower in fasting rat pups than in controls, although skin water content was still higher. To conclude, TEWL is very high in extremely preterm infants early after birth and then decreases at a slower rate than previously reported for a group of slightly more mature infants. This is the first time that the distribution and gene expression of AQP1 and AQP3 have been demonstrated in perinatal skin. The localization and expression of AQP in the skin might indicate that these water channels are involved in the regulation of skin hydration and transepidermal water transport in the fetus and newborn infant.

Submitted by Erika Demachki (erikademachki@gmail.com) on 2017-03-06T17:42:24Z No. of bitstreams: 2 Dissertação - Stéfanne Madalena Marques - 2017.pdf: 2931392 bytes, checksum: 0d7549b7390188445fbcb19cb5e18723 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2017-03-07T10:42:02Z (GMT) No. of bitstreams: 2 Dissertação - Stéfanne Madalena Marques - 2017.pdf: 2931392 bytes, checksum: 0d7549b7390188445fbcb19cb5e18723 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-03-07T10:42:02Z (GMT). No. of bitstreams: 2 Dissertação - Stéfanne Madalena Marques - 2017.pdf: 2931392 bytes, checksum: 0d7549b7390188445fbcb19cb5e18723 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-02-17 / Fundação de Amparo à Pesquisa do Estado de Goiás - FAPEG / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Several studies have determined the importance of intravenous infusion of sodium chloride (NaCl) solution in the cardiovascular recovery of hypovolemic hemorrhage (HH). Studies show the increased activity of the noradrenergic groups A1 and A2 in response to increased osmolarity in normovolemic rats. However, the participation of these neurons in the integration of the reflexive responses that lead to hemodynamic recovery and to the cardiovascular improvement induced by the infusion of hypertonic saline (HSI) solution during hypovolemia remain to be clarified. The present study sought to elucidate the participation of the noradrenergic groups A1 and A2 in cardiovascular recovery by HSI after HH in anesthetized rats. For this, mice should receive nanoinjections of 100 nL saporin (0.022 ng ∙ nl-1) or saporin-anti-DβH (0.105 ng ∙ nl-1) in the NTS region and/or bilaterally in the CVLM. After 20 days, the animals were instrumented to record the cardiovascular parameters: mean arterial pressure (MAP), heart rate (HR), renal vascular conductance (RVC), and aortic vascular conductance (AVC). HH was induced for 20 min by withdrawal of blood until a MAP reached about 60 mm Hg. Then, HIS (NaCl, 3M, 1.8 ml ∙ kg-1) / Diversos estudos determinaram a importância da infusão intravenosa de solução de cloreto de sódio (NaCl) hipertônica na recuperação cardiovascular da hemorragia hipovolêmica (HH). Estudos mostraram o aumento de atividade dos grupamentos noradrenérgicos bulbares A1 e A2 em resposta ao aumento da osmolaridade em ratos normovolêmicos. No entanto, a participação destes neurônios na integração das respostas reflexas que conduzem ao restabelecimento hemodinâmico e à melhora cardiovascular induzida pela infusão de solução salina hipertônica (SH) durante a hipovolemia ainda permanecem por ser esclarecidas. O presente estudo procurou elucidar a participação dos grupamentos noradrenérgicos bulbares A1 e A2 na recuperação cardiovascular por infusão de SH após HH em ratos anestesiados. Para isto, ratos Wistar receberam nanoinjeções de 100 nL de saporina (0,022 ng ∙ nl-1) ou saporina-anti-DβH (0,105 ng ∙ nl-1) na região NTS e/ou bilateralmente no CVLM. Após 15 dias, os animais foram instrumentalizados para registro dos parâmetros cardiovasculares: pressão arterial média (PAM), frequência cardíaca (FC), condutância vascular renal (CVR) e condutância vascular aórtica (CVA). A HH foi induzida durante 20 min pela retirada de sangue até que a PAM atingisse aproximadamente 60 mmHg. Em seguida, foi realizada a administração de solução SH (NaCl; 3M; 1,8 ml ∙ kg-1), e os parâmetros cardiovasculares foram registrados por mais 60 min. Os resultados mostraram que, nos animais com lesão do grupamento A2, após a infusão de SH a PAM retornou aos valores basais de maneira similar ao que ocorreu nos animais controle (sham A2: 109,4 ± 3,7 mmHg vs. Lesão A2: 108,6 ± 5,1 mmHg, 60 min após a infusão de SH); a FC reduziu significativamente em ratos controle e com lesão de A2 durante a HH e retornou aos níveis basais 10 min após infusão de SH (controle A2: 406,0 ± 10,6 bpm vs. Lesão A2: 368.8.1 ± 17,9 bpm); a HH e a infusão de solução SH não promoveu alterações nos valores basais de CVR em ambos os grupos (sham A2: Δ 3,0 ± 22,3%; Lesão A2: Δ -23,5 ± 16,6%, 20 min após a HH) e (sham A2: Δ 2,3 ± 18,8 vs. Lesão A2: Δ 7,3 ± 8,3%; 30 min após a infusão de SH). A CVA não foi alterada pela HH (sham A2: Δ -11,1 ± 6,6% vs Lesão A2: Δ 7,8 ± 11,6%; 20 min após a HH) ou infusão de SH (Sham: Δ -20,6 ± 7,8% vs. Lesão A2: Δ -4,4 ± 5,1%, 30 min após a infusão de SH). Nos animais com lesão combinada dos grupamentos A1 e A2, a infusão de SH não reestabeleceu os níveis de PAM (controle A1+A2: 104,9 ± 5,7 vs Lesão A1+A2: 64,2 ± 4,5 mmHg; p <0,05; 30 min após a infusão SH), permanecendo estes em níveis hemorrágicos até o final dos experimentos (controle A1+A2: 107,1 ± 3,3 vs Lesão A1+A2: 68,4 ± 4,2 mmHg; p <0,05; 60 min após infusão SH). A HH não alterou os valores basais de CVR (Sham A1+A2: Δ 4,7 ± 20,2% vs. Lesão A1+A2: Δ 2,9 ± 16,7%; 20 min após a HH); a solução SH, também, não foi capaz de alterar esse parâmetro nos grupos de animais controle e lesado (sham A1+A2: Δ: 0,1 ± 12,1% vs. Lesão A1+A2: Δ 29,4 ± 25,9%; 30 min após a infusão de SH). No grupo submetido a lesão A1+A2, a CVA não foi alterada pela HH em ambos os grupos (sham A1+A2: Δ -1,5 ± 16.3% vs. Lesão A1+A2: Δ -18,6 ± 6,3%; 20 min após a HH) ou pela infusão de solução de SH (sham A1+A2: Δ 20 ± 117% vs. Lesão A1+A2: Δ 9,5 ± 7,7%; 30 min após a infusão de SH). Os resultados indicam que o grupamento neuronal A2 não parece estar diretamente envolvido na recuperação cardiovascular por infusão de SH em ratos submetidos a HH e que a lesão simultânea dos grupamentos A1 e A2 foi capaz de suprimir a restauração da PAM em resposta à SH após a HH, indicando que a integridade desses grupamentos é essencial para a recuperação cardiovascular mediante hipernatremia aguda após a hipovolemia. Nosso estudo indica ainda que esses grupamentos não parecem estar diretamente envolvidos na regulação da reatividade vascular dos leitos analisados.

La sécheresse oculaire est une pathologie fréquente qui peut impacter fortement la qualité de vie des patients. D’origine multifactorielle complexe, elle présente de nombreuses étiologies et son diagnostic est difficile en raison de présentations cliniques variées, en termes de symptômes et de tests cliniques, et en l'absence d'un marqueur spécifique. En outre, elle ne bénéficie actuellement que d’une seule molécule thérapeutique, cependant non curative, la ciclosporine. Devenant un réel problème de santé publique, la recherche visant à une meilleure compréhension des mécanismes sous-jacents à son apparition reste indispensable. L'état actuel des connaissances sur la sécheresse oculaire reconnaît à l'inflammation et à l'hyperosmolarité un rôle central. Ce travail de thèse a eu pour objectif d'étudier le comportement pro-inflammatoire des cellules conjonctivales dans un modèle in vitro classique de sécheresse oculaire induite par une hyperosmolarité saline. Nous avons ainsi montré que les cellules conjonctivales sécrètent une chimiokine pro-inflammatoire majeure, CCL2/MCP-1, et que cette induction est totalement sous la dépendance du facteur de transcription osmoprotecteur NFAT5/TonEBP ainsi que partiellement liée à la voie des MAPKs et de NFκB. Nous avons également observé que cette induction était en partie inhibée par la ciclosporine et la dexaméthasone. Nous avons ensuite complété ce travail par l'étude de l'inflammasome à la fois sur ces cellules et sur des monocytes, type cellulaire majeur ciblé par CCL2, en utilisant différents activateurs classiques dans le modèle d’hyperosmolarité. Nos résultats ont montré l’absence d’activation de l’inflammasome par l'hyperosmolarité seule. En revanche, l'hyperosmolarité aurait un rôle inhibiteur de l’inflammasome dans les monocytes. Ces résultats ouvrent des pistes nouvelles d’exploration afin de mieux comprendre les relations entre monocytes et cellules épithéliales de la conjonctive. Ils nous ont permis d'identifier le rôle incontournable de cellules épithéliales conjonctivales dans l'apparition ou le maintien de l'inflammation dans la pathologie et de caractériser certaines voies intracellulaires impliquées dans ce processus, ouvrant de nouvelles perspectives en termes de thérapeutiques. / Dry eye disease is a common condition that significantly impacts the quality of life of patients. It is a complex multifactorial disease with many etiologies and a diagnosis recognized as difficult due to the multiple clinical presentations in terms of symptoms and clinical tests, and lacking of a reliable and specific marker. There is currently only one therapeutic molecule to treat this disease, cyclosporin. However it is not curative. Dry eye disease is becoming an important public health problem and it is necessary to focus research on its underlying mechanisms, as they remain largely unknown. The current state of knowledge in dry eye disease recognizes inflammation and hyperosmolarity as central elements in the pathology. This work aimed to study the pro-inflammatory behavior of conjunctival cells in an in vitro model of dry eye disease by NaCl-induced hyperosmolarity. We showed that conjunctival cells secrete a major pro-inflammatory chemokine known as CCL2/MCP-1. This induction depends entirely on the osmoprotectant transcription factor NFAT5/TonEBP and is partially related to the MAPKs and the NFκB pathways. We showed that the process could be partially inhibited by cyclosporin and dexamethasone. We also studied the inflammasome in conjunctival cells and monocytes, the major cell type targeted by CCL2, using various classical inflammasome activators in this hyperosmolarity model. We did not observe any inflammasome activation induced by hyperosmolarity alone. On the other hand, hyperosmolarity shows signs of inhibiting inflammasome activation in monocytes. These results open new ways of understanding the relations between monocytes and conjunctival epithelial cells. They highlight the crucial role of the conjunctival epithelial cell type in the inflammation process in dry eye disease and make it possible to characterize intracellular pathways involved in this process, opening new therapeutic prospects.

Dedifferentiation and proliferation of retinal pigment epithelial (RPE) cells are characteristics of retinal diseases. Dedifferentiation is likely associated with changes of inwardly rectifying potassium (Kir) channels. The roles of Kir4.2 channels in viability, and proliferation of cultured RPE cells were investigated. Gene expression levels were determined using qRT-PCR. RPE cells expressed Kir2.1, 2.2, 2.4, 3.2, 4.1, 4.2, 6.1, and 7.1 mRNA. Kir4.2 protein was verified by immunocytochemistry and Western blotting. Kir4.2 mRNA in cultured cells was upregulated by hypoxia (hypoxia mimetic CoCl2 or 0.2% O2) and extracellular hyperosmolarity (addition of high NaCl or sucrose). Kir4.2 mRNA was suppressed by vascular endothelial growth factor (VEGF), blood serum, and thrombin whereas platelet-derived growth factor (PDGF), basic fibroblast growth factor (bFGF), and transforming growth factor-1 (TGF-1) increased it. Hyperosmotic Kir4.2 gene expression was mediated by TGF-1 receptor signaling while hypoxic gene transcription was dependent on PDGF receptor signaling. VEGF receptor-2 blockade increased Kir4.2 mRNA level under control, hyperosmotic, and hypoxic conditions. SiRNA-mediated knockdown of Kir4.2 decreased the cell viability and proliferation under control and hyperosmotic conditions. Kir4.2 channels play functional roles in maintaining the viability and proliferation of RPE cells. Downregulation of Kir4.2 by VEGF, via activation of VEGF receptor-2 and induction of blood-retinal barrier breakdown, may contribute to decreased viability of RPE cells under pathological conditions.

Neste trabalho investigamos a interação entre ATP-glutamato na modulação de potenciais de ação e atividade sináptica de neurônios PVN-RVLM, além de avaliar se esta interação induziria mudanças na atividade simpática lombar (ANSL) por estímulo osmótico. Utilizamos de técnicas de imunohistoquímica, whole-cell patch clamp e registro eletroneurográfico. Observou-se que o ATP aumenta a frequência de potenciais de ação em neurônios PVN-RVLM, efeito bloqueado por acido quinurênico (KYN) e PPADS. A injeção de ATP no PVN aumenta a ANSL (25 nmol: 72%), um efeito atenuado por PPADS e/ou KYN, e também por CNQX. O ATP não afeta a função sináptica, mas aumenta correntes glutamatérgicas induzidas por aplicação AMPA em 52%, a qual foi bloqueada por PPADS ou por quelação de Ca2+ intracelular. Além disso, o estímulo osmótico ativa neurônios do PVN que expressam receptores P2X2 e potencia as correntes mediadas por AMPA (53%), um efeito bloqueado por PPADS. Finalmente, demonstrou-se que receptores P2 no PVN são importantes na simpatoexcitação induzida por estímulo osmótico agudo. / In the present study we investigate the interaction of ATP-glutamate on the firing activity and synaptic function in PVN-RVLM neurons, besides whether that interaction would be translated in changes on sympathetic nerve activity (SNA) induced by osmotic stimulus. Immunohistochemistry, whole-cell patch clamp and electroneurography technical approaches were used. Our data have shown that ATP increases firing rate of PVN-RVLM neurons, an effect blocked by kynurenic acid (KYN) or PPADS. ATP injection into the PVN enhanced SNA (72%), which was attenuated by PPADS and/or KYN, or CNQX. ATP did not affect synaptic function but, glutamatergic currents evoked by AMPA application were augmented with ATP (AMPA area: 52%), blocked by PPADS and chelation of intracellular Ca2+. In addition, we observed that acute osmotic stimulus activates P2X2 expressing neurons in the PVN. Moreover, an osmotic challenge potentiated AMPA responses (53%), an effect blocked by PPADS. Finally, we demonstrated that P2 receptors in the PVN are important for osmotically-driven sympathoexcitation.

O aumento da osmolaridade plasmática é conhecido como hiperosmolaridade e é resultado do aumento do aporte de sódio ou, da diminuição do volume plasmático de água. Trata-se de um desafio orgânico capaz de iniciar uma série de respostas neuro-hormonais que incluem a liberação de vasopressina e aumento da atividade simpática, com consequente elevação da pressão arterial. Descrever o papel do sistema nervoso autonômico no desenvolvimento da hipertensão arterial secundária a ingestão de sódio é essencial para elucidar os mecanismos envolvidos na gênese desta patologia. Neste sentido, o RVLM é um importante alvo de estudos, dado seu envolvidos na regulação da atividade simpática, via projeções para a CIML. O RVLM possui um grupo neuronal denominado C1 caracterizado pela presença da enzima PNMT; a ativação destes neurônios já foi descrita em resposta a diversos desafios orgânicos tais como hipóxia, dor, hemorragia, inflamação, hipotensão e hipoglicemia. Sendo a hiperosmolaridade um desequilíbrio da homeostase propusemos investigar a possível participação dos neurônios adrenérgicos do grupamento C1 sobre a hipertensão secundária ao desafio hiperosmótico desencadeado pela ingestão crônica de solução de 2% cloreto de sódio (salina hipertônica de NaCl 2%) por 7 dias. Nossos resultados nos permitem concluir que: 1) a injeção de anti-D&betaH-saporina na região do RVLM causou a depleção de neurônios TH+ nas regiões C1 e A5; 2) A depleção dos neurônios TH+ não alterou o comportamento de ingestão de sódio e, tampouco os valores de hematócrito e osmolaridade plasmática resultados da exposição ao hiperosmótico durante 7 dias, comparado aos animais controle; 3) A lesão prévia dos neurônios do C1 e A5 inibe o desenvolvimento da hipertensão secundária ao estímulo hiperosmótico por ingestão de NaCl 2%. Além disso, propusemos também estudar como estariam as respostas cardiovasculares e de controle hidroeletrolítico em indivíduos normotensos e previamente hipertensos frente a diferentes intensidades de estímulo hiperosmótico desencadeado pela ingesta de salina hipertônica de NaCl 2%. Os resultados demonstraram que 1) a ingestão de sódio desencadeia uma elevação da pressão arterial de maior magnitude nos SHR, quando comparado aos animais Wistar; 2) que não parece estar envolvida com diferenças no balanço hidroeletrolítico, uma vez que observou-se repostas similares entre as duas linhagens; 3) houve ainda, um aumento da expressão do RNAm para neuropeptídeo vasopressina (VP) no núcleo paraventricular do hipotálamo (PVN) tanto em Wistar quanto em SHR decorrente da ingestão de NaCl 2% durante 7 dias. Até o presente momento nossos resultados permitem duas considerações acerca dos mecanismos envolvidos nas repostas geradas frente desafios da osmolaridade: 1) os neurônios TH+ e, potencialmente do grupamento C1, estão envolvidos no desenvolvimento da hipertensão arterial em situações de desafio crônico da osmolaridade; 2) em animais hipertensos (SHR) o estímulo hiperosmótico gera uma elevação da pressão arterial de maior magnitude em comparação aos animais normotensos, fato que sugerimos envolver mecanismos de controle neural da pressão arterial, uma vez que não se observou alterações significativas nos parâmetros hidroeletrolítico e função renal entre as duas linhagens. / Plasma osmolarity increases is known as hyperosmolarity and it is a consequence of high sodium intake or decrease of water plasma content. It is an organic imbalance that elicits neurohormonal responses including release of vasopressin and increased in sympathetic activity, with consequent elevation of blood pressure. To describe the role of the autonomic nervous system in the development of sodium induced hypertension is critical to elucidate the mechanisms involved in the genesis of this pathology. In this sense, the RVLM is an important target, given its involved in the regulation of sympathetic activity, via CIML projections. The RVLM has a neuronal group known as C1 that present the PNMT enzyme; the activation of these neurons has already been described in response to several organic challenges such as hypoxia, pain, hemorrhage, inflammation, hypotension and hypoglycemia. Since hyperosmolarity is an homeostasis imbalance, we propose to investigate the role of adrenergic C1 neurons on sodium induced hypertension, triggered by the chronic ingestion of NaCl2% solution during 7 days. Our results allow us to conclude that: 1) the anti-D&betaH-saporin injection in the RVLM led to a depletion of TH+ neurons in the C1 and A5 regions; 2) Depletion of TH + neurons did not alter the sodium intake behavior, hematocrit and plasma osmolality values result from 7 days NaCl 2% exposure, compared to control animals; 3) Depletion of TH+ in C1 and A5 regions inhibits the development of sodium induced hypertension . In addition, we also proposed to investigate the cardiovascular and hydroelectrolytic responses elicits in normotensive and hypertensive rats, in response to different intensities of hyperosmotic stimulation triggered by the ingestion of hypertonic saline of NaCl 2%. The results demonstrated that: 1) the increase in blood pressure triggers by NaCl 2% intake is higher in SHR when compared to Wistar animals; 2) that does not appear to be involved with differences in hydroelectrolyte balance, since similar responses were observed between the two strains; 3) there was also an increase in mRNA expression for neuropeptide vasopressin (VP) in the paraventricular nucleus of the hypothalamus (PVN) in both strains, Wistar and SHR, in consequence of 7 days NaCl 2% intake. Our results allow two considerations about the mechanisms involved in the responses elicits by osmolarity challenges: 1) TH+ neurons and, potentially C1 neurons, are involved in the development sodium induced hypertension and; 2) in SHRs the hyperosmotic stimulus generates a higher blood pressure increase in comparison to normotensive animals, which seems to be associated with sympathoexcitatory components, since no significant alterations were observed in the hydroelectrolytic parameters and renal function between the two strains.

Made available in DSpace on 2016-06-02T19:22:11Z (GMT). No. of bitstreams: 1 6151.pdf: 1975366 bytes, checksum: 23b842452d75ee4bd80f5408eccc025c (MD5) Previous issue date: 2014-08-26 / Universidade Federal de Minas Gerais / Sodium intake is induced by facilitatory signals, such as angiotensin II (ANG II) and aldosterone. Hyperosmolarity and central cholinergic activation, classic antinatriorexigenic stimuli, also induce NaCl intake when the inhibitory mechanisms of the lateral parabrachial nucleus (LPBN) are deactivated. In the present study, we investigated the possible interaction between osmoreceptors and cholinergic and angiotensinergic mechanisms in the control of water and NaCl intake induced by different dipsogenic and/or natriorexigenic stimuli combined with the blockade of LPBN inhibitory mechanisms. Rats with stainless steel cannulas implanted in the lateral ventricle (LV) or subfornical organ (SFO) and bilaterally into the LPBN were used to study the effects of injections of atropine (muscarinic cholinergic antagonist), losartan or ZD 7155 (AT1 receptor antagonists) into the LV or SFO on water and 0.3 M NaCl intake induced by bilateral injections of moxonidine (&#945;2- adrenoceptor/imidazoline agonist) into the LPBN combined with a) plasma hyperosmolarity induced by intragastric (ig) 2 M NaCl; b) injections of carbachol (cholinergic agonist) into the LV or SFO; c) subcutaneous injections of furosemide (FURO) and captopril (CAP); d) injection of ANG II into the LV. Additionally, we also investigated whether acute application of osmotic, angiotensinergic and cholinergic stimuli would activate cultured SFO dissociated cells and if the same cell would be activated by different stimuli. In rats treated with ig 2 M NaCl, injections of moxonidine (0.5 nmol/0.2 &#956;l) into the LPBN increased water and 0.3 M NaCl intake. Injections into the LV or SFO of atropine (20 nmol/1.0 &#956;l and 2 nmol/0.1 &#956;l, respectively) or losartan (100 &#956;g/1.0 &#956;l and 1 &#956;g/0.1 &#956;l, respectively) abolished water and 0.3 M NaCl intake in rats treated with ig 2 M NaCl combined with moxonidine into the LPBN. Moxonidine injected into the LPBN also increased water and 0.3 M NaCl intake induced by FURO + CAP, injections of ANG II (50 ng/1.0 &#956;l) and carbachol (4 nmol/1.0 &#956;l) into the LV or carbachol (0.5 nmol/0.1 &#956;l) into the SFO. The blockade of AT1 receptors with injections of losartan into the LV or ZD 7155 (1 &#956;g/0.1 &#956;l) into the SFO abolished water and 0.3 M NaCl intake in rats treated with carbachol into the LV or SFO combined with LPBN injections of moxonidine. However, atropine injected into the LV, despite reducing water intake, did not change 0.3 M NaCl intake in rats treated with FURO + CAP or injection of ANG II into the LV combined with injections of moxonidine into the LPBN. Injections of losartan into the LV reduced 0.06 M sucrose intake, but did not change food intake induced by 24 h of food deprivation. Finally, in vitro studies showed that osmotic, angiotensinergic and cholinergic stimuli activate SFO dissociated cells and that different stimuli can activate the same SFO cell. Therefore, the results of the present study suggest that different stimuli, such as hyperosmolarity and central cholinergic activation, facilitate NaCl intake through activation of central angiotensinergic mechanisms. / A ingestão de sódio é induzida por sinais facilitatórios, como angiotensina II (ANG II) e aldosterona. A hiperosmolaridade e a estimulação colinérgica central, estímulos classicamente considerados antinatriorexigênicos, também induzem ingestão de NaCl quando os mecanismos inibitórios do núcleo parabraquial lateral (NPBL) são bloqueados. No presente estudo, investigamos a possível interação entre osmorreceptores e mecanismos colinérgicos e angiotensinérgicos centrais no controle da ingestão de água e NaCl induzida por diferentes estímulos dipsogênicos e/ou natriorexigênicos combinados com bloqueio dos mecanismos inibitórios do NPBL. Em ratos com cânulas de aço inoxidável implantadas no ventrículo lateral (VL) ou órgão subfornical (OSF) e bilateralmente no NPBL, foram estudados os efeitos de injeções de atropina (antagonista colinérgico muscarínico), losartan ou ZD 7155 (antagonistas de receptores AT1) no VL ou diretamente no OSF na ingestão de água e NaCl 0,3 M induzida por injeções bilaterais de moxonidina (agonista adrenérgico &#945;2/imidazólico) no NPBL combinadas com: a) hiperosmolaridade plasmática induzida por sobrecarga intragástrica de NaCl 2 M; b) injeções de carbacol (agonista colinérgico) no VL ou OSF; c) injeções subcutâneas de furosemida (FURO) e captopril (CAP); d) injeção de ANG II no VL. Adicionalmente, também foi investigado se a aplicação aguda de estímulos osmóticos, angiotensinérgico e colinérgico ativariam neurônios dissociados do OSF mantidos em cultura e se um mesmo neurônio seria ativado por diferentes estímulos. Em ratos tratados com NaCl 2 M ig, injeções de moxonidina (0,5 nmol/0,2 &#956;l) no NPBL aumentaram a ingestão de água e NaCl 0,3 M. Injeções no VL ou OSF de atropina (20 nmol/1,0 &#956;l e 2 nmol/0,1 &#956;l, respectivamente) ou losartan (100 &#956;g/1,0 &#956;l e 1 &#956;g/0,1 &#956;l, respectivamente) aboliram a ingestão de água e NaCl em ratos tratados com NaCl 2 M ig que receberam injeções de moxonidina no NPBL. Injeções de moxonidina também aumentaram a ingestão de água e NaCl 0,3 M induzida por FURO + CAP, injeções de ANG II (50 ng/1,0 &#956;l) e carbacol (4 nmol/1,0 &#956;l) no VL ou carbacol (0,5 nmol/0,1 &#956;l) no OSF. O bloqueio de receptores AT1 com injeções de losartan no VL ou ZD 7155 (1 &#956;g/0,1 &#956;l) no OSF aboliu a ingestão de água e NaCl 0,3 M em ratos tratados com injeção de carbacol no VL ou OSF combinada com injeções de moxonidina no NPBL. No entanto, injeção de atropina no VL, apesar de reduzir a ingestão de água, não alterou a ingestão de NaCl 0,3 M em ratos tratados com FURO + CAP ou injeção de ANG II no VL combinados com injeções de moxonidina no NPBL. Injeções de losartan no VL reduziram a ingestão de sacarose 0,06 M, mas não alteraram a ingestão de ração induzida por privação alimentar por 24 h. Finalmente, os estudos in vitro mostraram que estímulos osmóticos, angiotensinérgico e colinérgico ativam as células dissociadas do OSF e que diferentes estímulos podem ativar uma mesma célula do OSF. Portanto, os resultados do presente estudo sugerem que diferentes estímulos, tais como hiperosmolaridade e ativação colinérgica central, facilitam a ingestão de NaCl através da ativação de mecanismos angiotensinérgicos centrais.