Effect of some drugs on reflex vasodilatation of hand produced by radiant heating of trunk

Abstract

The effect of some drugs on reflex vasodilatation in the hand was studied. Bretylium tosylate and phenoxybenzamine abolished the reflex vasodilator response in the hand caused by cradle heating of the chest. Alpha methyl dopa, nethalide, and atropine had no effect on this response. It is suggested that the tonic constriction of hand vessels maintained by sympathetic fibers and alpha adrenergic constrictor receptors is temporarily interrupted by 40 sec cradle heating of the chest and that this produces the observed increase in hand blood flow. The reflex increase in hand blood flow with short cradle heating of the chest appears to utilize a common efferent pathway with the vasodilator response produced in the hand by prolonged heating of the legs. On the afferent side, however, these reflexes use different mechanisms. afferent and efferent pathways; alpha methyl dopa; nethalide; atropine; receptors on hand vessels; bretylium tosylate; phenoxybenzamine Submitted on February 24, 1964