Skeletal Muscle Microvessels

Adrenergic constriction of skeletal muscle arterioles, particularly small terminal arterioles, is opposed by decreased blood flow or increased metabolic rate. Our previous studies indicate that neural constriction of large arterioles, which have both postjunctional a1and a2-adrenoceptors, is mediated by a1-receptors; small arterioles depend on a2-receptors. Also, a,2 but not ca, constriction is reduced by acidosis. Differential sensitivity of ae1 versus a2 constriction to metabolic signals such as H' may underlie the sensitivity of arteriolar adrenergic constriction to metabolic inhibition. To examine this hypothesis, we studied the effect of reduced perfusion