Impact of heat shock on endothelium-mediated reactions of isolated rat aorta

Abstract

In this study of the impact of heat shock on the functional state of vascular endothelium, injection of rats with the NO synthase blocker Nω-nitro-L-arginine immediately after heat shock results in a much lower fall in arterial pressure than in control animals, and the heat shock increases the inhibitory action of endothelium on both the force and rate of norepinephrine-induced contractions in isolated rat aorta, without any alterations in the sensitivity of adrenoreceptors; the endothelium-dependent aortal relaxation in response to acetylcholine also increases. It is shown that enhancement of endothelium-dependent vasodilator responses and inhibition of vasoconstrictor responses may contribute to the fall of arterial pressure and the development of collapse-like states in heat shock.