An Electrophysiological Study of the Sympathetic Vasodilator Fibers of the Limb

Abstract

Electric stimulation of a restricted region in the hypothalamus of the cat evoked a pronounced dilation of the muscular vessels of the hind limbs. Due to compensatory vasconstriction of other regions the general blood pressure, however, was relatively unchanged. In response to such a stimulation an increased outflow of impulses mediated by postganglionic nonmyelinated fibers to the muscles of the limb could be recorded. Small amts. of atropine abolished the vasodilator response but did not influence the occurrence of the slow potential waves. Thus the existence of cholinergic sympathetic vasodilator fibers, distributed to the muscular vessels of the cat''s limb has been directly proved.