Effect of mitochondrial complex III inhibitors on the regulation of vascular tone in porcine coronary artery.

In order to gain insight into the regulation of vascular tone by mitochondria, the effects of mitochondrial complex III inhibitors on contractile responses in porcine isolated coronary arteries were investigated. Segments of porcine coronary arteries were set up for isometric tension recording and concentration response curves to contractile agents were carried out in the absence or presence of the complex III inhibitors antimycin A or myxothiazol. Activity of AMP kinase was determined by measuring changes in phosphorylation of AMP kinase at Thr172.