Effect of acute oral beta adrenergic blockade on muscle blood flow in man

Abstract

We have determined the effect of beta blocking drugs in man to ascertain whether cardioselectivity or intrinsic sympathomimetic activity influence muscle blood flow response to exercise. Exercise muscle blood flow was determined using a miniaturised lightweight cadmium telluride detector attached to the skin surface. Mean exercise muscle blood flow for the six subjects, during a constant work load, did not differ significantly either for predosing values on the six separate study days or at 2, 4 and 6 h after dosing with placebo. All the beta blocking agents caused a reduction in exercise muscle blood flow. Propranolol caused significant reduction in muscle blood flow at 2 h only. Metoprolol and atenolol produced the greatest and most prolonged effect and oxprenolol the smallest effect on exercise muscle blood flow. Intrinsic sympathomimetic activity may protect against reduction in exercise muscle blood flow in man.