The Effect of Prolonged Sodium Depletion and of Hydrallazine Hydrochloride and Hexamethonium Bromide on the Digital Vascular Resistance in Primary Hypertension

The effect of dietary sodium depletion and of oral hydrallazine hydrochloride and parenteral hexamethonium bromide on the digital circulation was studied by repeated measurements of pressure and flow before and after inhibition of sympathetic nerve discharge in a small series of hypertensive patients. Sodium depletion had no demonstrable effect on neurogenic digital vasoconstriction but produced either a decrease in intrinsic digital vascular resistance, a decrease in intrinsic flow, or both. The chief effect of the drugs studied, in contrast, was elimination of neurogenic digital vasoconstriction.