Effect of carotid and aortic baroreceptors on cardiopulmonary reflex: the role of autonomic function

Autor(es)

Fernandes, T. L. ^[1] ; Piratello, A. C. ^[1] ; Farah, V. ^[2] ; Fiorino, P. ^[2] ; Moreira, E. D. ^[1] ; Irigoyen, M. C. ^[1] ; Krieger, E. M. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Unidade Hipertensao, INCOR, FM, BR-05403000 Sao Paulo - Brazil

^[2] Univ Presbiteriana Mackenzie, Ctr Ciencias Biol & Saude, Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Brazilian Journal of Medical and Biological Research; v. 43, n. 7, p. 681-686, JUL 2010.
• Citações Web of Science: 1

Resumo

We determined the sympathetic and parasympathetic control of heart rate (HR) and the sensitivity of the cardiopulmonary receptors after selective carotid and aortic denervation. We also investigated the participation of the autonomic nervous system in the Bezold-Jarish reflex after selective removal of aortic and carotid baroreceptors. Male Wistar rats (220-270 g) were divided into three groups: control (CG, N = 8), aortic denervation (AG, N = 5) and carotid denervation (CAG, N = 9). AG animals presented increased arterial pressure (12%) and HR (11%) compared with CG, while CAG animals presented a reduction in arterial pressure (16%) and unchanged HR compared with CG. The sequential blockade of autonomic effects by atropine and propranolol indicated a reduction in vagal function in CAG (a 50 and 62% reduction in vagal effect and tonus, respectively) while AG showed an increase of more than 100% in sympathetic control of HR. The Bezold-Jarish reflex was evaluated using serotonin, which induced increased bradycardia and hypotension in AG and CAG, suggesting that the sensitivity of the cardiopulmonary reflex is augmented after selective denervation. Atropine administration abolished the bradycardic responses induced by serotonin in all groups; however, the hypotensive response was still increased in AG. Although the responses after atropine were lower than the responses before the drug, indicating a reduction in vagal outflow after selective denervation, our data suggest that both denervation procedures are associated with an increase in sympathetic modulation of the vessels, indicating that the sensitivity of the cardiopulmonary receptors was modulated by baroreceptor fibers. (AU)

• Processo FAPESP: 99/09959-0 - Participacao do sistema nervoso autonomo na sensibilidade do reflexo cardiopulmonar em ratos com desnervacao seletiva dos pressorreceptores e quimiorreceptores.
• Beneficiário: Tiago Lazzaretti Fernandes
• Modalidade de apoio: Bolsas no Brasil - Iniciação Científica