[Effect of changes in sympathetic vasomotor tonus on vasodilatatory effect of catecholamines].

The study of resistances modifications in the femoral vascular bed during bilateral carotide occlusion supports the hypothesis of an inhibitory action of isoprenaline on norepinephrine release by the sympathetic post-ganglionnic fibres. This action explain the relations between isoprenaline vasodilator potency and sympathetic activity level.