RESUMO
The regional hemodynamic effects of endothelin-1 (ET-1) were studied in Wistar-Kyoto rats. Endothelin-1 caused a transient increase in blood flow in the carotid and femoral arteries but a decrease in flow in the renal and mesenteric arteries. The resistance in the carotid and femoral beds decreased while it increased in the renal and mesenteric beds. Subsequently there was a variable increase in resistance in all vascular beds with a maximal increase in the renal bed. Thus, ET-1 initially causes a selective vasorelaxation in musculocutaneous beds but not in visceral beds; the cause of this selectivity is unknown.
Assuntos
Artérias Carótidas/efeitos dos fármacos , Endotelinas/farmacologia , Artéria Femoral/efeitos dos fármacos , Artérias Mesentéricas/efeitos dos fármacos , Artéria Renal/efeitos dos fármacos , Vasoconstrição/efeitos dos fármacos , Vasodilatação/efeitos dos fármacos , Animais , Artérias Carótidas/fisiologia , Avaliação Pré-Clínica de Medicamentos , Artéria Femoral/fisiologia , Masculino , Artérias Mesentéricas/fisiologia , Ratos , Ratos Endogâmicos WKY , Fluxo Sanguíneo Regional/efeitos dos fármacos , Artéria Renal/fisiologia , Fatores de Tempo , Resistência Vascular/efeitos dos fármacosRESUMO
The effects of vibration on the neurosecretory system of the brain were studied using the method of autoradiography. Both control and exposed to vibration (for 6 or 12 days) guinea pigs were injected with tritiated methionine and the uptake of the isotope was determined after 1, 6, 12, 24 h. Some differences were found in the number of silver grains in the brain neurosecretory system between the controls and both experimental groups. These differences, were however, not statistically significant.
Assuntos
Encéfalo/fisiologia , Metionina/metabolismo , Sistemas Neurossecretores , Vibração , Animais , Autorradiografia , Cobaias , Hipotálamo/metabolismo , Masculino , Metionina/administração & dosagem , Métodos , Neurossecreção , Hipófise/metabolismo , Fatores de Tempo , TrítioRESUMO
The investigations were carried out on guniea pigs subjected to vibration of varying parameters and varying duration. Isotope method with 35-S-cysteine administered suboccipitally was used, and the investigated material included supraoptic nuclei and the pars nervosa of the hypophysis. Exposure to vibration was followed by more rapid release of labelled cysteine as demonstrated by reduction in the number of silver grains in autoradiograms.