Biomedical vignette

Abstract

Exercise training produces numerous adaptive alterations in the circulatory system [9], including changes in vasomotor tone. The underlying mechanisms, however, are controversial. Chen et al. [4] observed that after treadmill training for 8 weeks, both aorta and mesenteric artery from rats exhibit an enhanced relaxation in response to acetylcholine. This endotheliurn-dependent vasodilatation is reversed by the nitric oxide synthase inhibitor, L-NAME, or the calcium-activated K+ (Kca) channel inhibitor, charybdotoxin. It is concluded that vasodilatation seen after exercise may result from the release of nitric oxide and activation of Kca channels in the vascular bed.