Participação do grupamento catecolaminérgico A2 do núcleo do trato solitário comissural nos ajustes cardiovasculares e do equilíbrio hidroeletrolitíco induzidos por alterações da osmolaridade ou volume plasmático
Data
2010-08-13
Autores
Freiria-Oliveira, André Henrique [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
É de extrema importância para o funcionamento do organismo a manutenção da osmolaridade e volume dos líquidos corporais. O sistema nervoso central (SNC) tem um papel fundamental para esta manuntenção. O núcleo do trato solitário (NTS) é o sítio primário das aferências cardiovasculares e de osmorreceptores periféricos e se projeta à areas prosencefálicas envolvidas com a regulação cardiovascular e do equilíbrio hidroeletrolítico. Desta forma, o NTS pode fazer a ligação entre as aferências viscerais e o SNC e participar dos ajustes necessários a regulação da osmolaridade e da volemia. A maior porção dos neurônios do grupamento catelocaminérgicos A2 do bulbo está localizada na porção comissural no NTS (NTScom). Assim, os objetivos deste estudo foram: a) estudar os efeitos na pressão arterial, na ingestão de água e na excreção renal subsequentes a administração de NaCl 2 M, estímulo osmótico agudo, em ratos com lesão seletiva dos neurônios A2 do NTScom; b) estudar os efeitos na expressão da proteína c-FOS subsequente a administração de NaCl 2 M, em ratos com lesão seletiva dos neurônios A2 do NTScom, c) estudar alterações na expressão de RNAm no NTS após a administração de NaCl 2 M, d) estudar os efeitos na pressão arterial subsequentes a hemorragia hipotensiva, em ratos com lesão seletiva dos neurônios A2 do NTScom. Ratos Holtzman (280-320 g) ou ratos Sprague-Dawley (230-280 g) foram utilizados neste estudo. Para a lesão seletiva dos neurônios A2 do NTScom ou lesão fictícia (LF), os animais foram submetidos a uma craniotomia parcial e a superfície dorsal do bulbo foi exposta. A lesão seletiva dos neurônios noradredérgicos foi realizada por meio da injeção no...
The central nervous system has an important role controlling the mechanisms involved in the regulation of body fluid osmolality. The nucleus of the solitary tract (NTS) is the primary site of cardiovascular and peripheral osmoreceptors afferents and projects to prosencephalic areas involved in hydroelectrolytic balance and cardiovascular regulation. The great part of the catecholaminergic neurons of the A2 group is located in the commissural part of the NTS (NTScom). Thus, the aims of this study were: a) to verify the effects in the arterial pressure, water intake and renal excretion observed after intragastric (ig) 2 M NaCl in rats with lesion of the A2 neurons of the NTScom, b) to verify the effects in the c-Fos expression after ig 2 M NaCl in rats with lesion of the A2 neurons of the NTScom, c) to study changes in gene expression on NTS after ig 2 M NaCl, d) to study the effects in arterial pressure after hypotensive hemorrhage in rats with lesion of the A2 neurons of the NTScom.Male Holtzman rats (280-320 g) or Sprague-Dawley (250-280 g) were used. For the A2 lesion of the NTScom, a partial craniotomy of the occipital bone was performed, and the dorsal surface of the brainstem was exposed. The lesion was performed by the injection of the toxine anti-dopamine-β-hydroxylase-saporin into the NTScom to destroy A2 neurons in this region. Sham lesioned rats anti-IgG-saporin was injected into the NTScom. We observed that in A2 lesioned rats, ig 2 M NaCl induced a vasopressin dependent-pressor response, for at least 60 min. The water intake induced by sodium overload was also incremented in A2 lesioned rats, however the natriuresis and dieresis after 2 M NaCl were similar in both groups. After 2 M NaCl... (Complete abstract click electronic access below)
The central nervous system has an important role controlling the mechanisms involved in the regulation of body fluid osmolality. The nucleus of the solitary tract (NTS) is the primary site of cardiovascular and peripheral osmoreceptors afferents and projects to prosencephalic areas involved in hydroelectrolytic balance and cardiovascular regulation. The great part of the catecholaminergic neurons of the A2 group is located in the commissural part of the NTS (NTScom). Thus, the aims of this study were: a) to verify the effects in the arterial pressure, water intake and renal excretion observed after intragastric (ig) 2 M NaCl in rats with lesion of the A2 neurons of the NTScom, b) to verify the effects in the c-Fos expression after ig 2 M NaCl in rats with lesion of the A2 neurons of the NTScom, c) to study changes in gene expression on NTS after ig 2 M NaCl, d) to study the effects in arterial pressure after hypotensive hemorrhage in rats with lesion of the A2 neurons of the NTScom.Male Holtzman rats (280-320 g) or Sprague-Dawley (250-280 g) were used. For the A2 lesion of the NTScom, a partial craniotomy of the occipital bone was performed, and the dorsal surface of the brainstem was exposed. The lesion was performed by the injection of the toxine anti-dopamine-β-hydroxylase-saporin into the NTScom to destroy A2 neurons in this region. Sham lesioned rats anti-IgG-saporin was injected into the NTScom. We observed that in A2 lesioned rats, ig 2 M NaCl induced a vasopressin dependent-pressor response, for at least 60 min. The water intake induced by sodium overload was also incremented in A2 lesioned rats, however the natriuresis and dieresis after 2 M NaCl were similar in both groups. After 2 M NaCl... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Hipertensão, Homeostasis, Hypertension
Como citar
FREIRIA-OLIVEIRA, André Henrique. Participação do grupamento catecolaminérgico A2 do núcleo do trato solitário comissural nos ajustes cardiovasculares e do equilíbrio hidroeletrolitíco induzidos por alterações da osmolaridade ou volume plasmático. 2010. 100 f. Tese (doutorado) - UNESP/UFSCAR. Programa Interinstitucional de Pós Graduação em Ciências Fisiológicas, 2010.