Sistema colinérgico central modula os ajustes dos sistemas cardiovascular e termorregulatório induzidos pelo exercício físico até a fadiga

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

ABSTRACT The purpose of this study was to verify if the cardiovascular and thermoregulatory adjustments mediated by central cholinergic receptors and peripheral cathecolamines during the physical exercise until fatigue. Wistar rats weighting 278 ± 5 g, were submitted to bilateral adrenodemedullation (ADM) or sham (SHAM) surgery. After recovery, the animals were subjected to 3 additional surgeries: implantations of intracerebroventricular guide cannulae; of aortic catheter into left carotid and intraperitoneal implantation of thermal sensor. The animals were divided into 4 groups: SHAM or ADM groups submitted to exercise at 24 m/min and 5% inclination (~80% of VO2max) until fatigue, SHAM or ADM groups with no exercise. Each group received 2 experimental treatments: icv injection of 2 µL of 5 x 10-3 M physostigmine (FIS) or 0,15 M NaCl (SAL). Environmental temperature was 24,7 ± 0,1ºC. No difference was found between groups or treatments in time to fatigue. In ADM group the FIS increased exercise mean blood pressure (ADM-EX-SAL 16 ± 4mmHg vs ADM-EX-FIS 33 ± 3mmHg, p<0,05). The intraperitoneal temperature increased in the ADM-EX group, but wasn´t different between the treatments (ADMEX- SAL 0,5 ± 0,1°C vs ADM-EX-FIS 0,5 ± 0,1°C). The tail temperature increased in the ADM-EX-FIS group (ADM-EX-SAL 2,9 ± 0,6°C vs ADM-EX-FIS 4,1 ± 0,°C, p<0,05). No difference was found between ADM and SHAM. Heat loss and cardiovascular adjustments modulated by the central cholinergic receptors during exercise are independ from the action of peripheral cathecolamines.

ASSUNTO(S)

pressão arterial medição teses. fisostigmina decs fadiga teses. processos fisiológicos cardiovasculares decs corpo temperatura regulação teses. exercícios físicos aspectos fisiológicos teses. receptores colinérgicos decs

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