THE HEMODYNAMIC EFFECTS OF HYPOTENSIVE DRUGS IN MAN. I. VERATRUM VIRIDE1

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Abstract
V. viride admd. to hypertensive patients produces the following hemo dynamic effects: Blood flow through muscular, renal, and hepatic-portal areas usually falls initially and then returns to approx. control levels despite a continued hypotensive response. Full peripheral vasodilatation characteristically follows rather than accompanies the initial reduction in arterial pressure. The output of the compensated heart remains essentially unchanged after arterial pressure is reduced. In congestive heart failure cardiac output may increase and the elevated pulmonary arterial pressure may fall. Atropine abolishes the bradycardia induced by V. viride but only partially reverses the hypotension. Effective renal plasma flow decreases only transiently and returns to control values despite a continued reduction in arterial pressure after Veratrum. Glomerular filtration rate (inulin) follows a similar pattern in most cases, but occasional remains below control values. Oliguria occurs after the initial injn. of V. viride but disappears when the hypotensive effect is continued by repeated oral admn. of the drug. The oliguria is not related directly to the arterial pressure, glomerular filtration rate or renal plasma flow, but appears to be due to a specific antidiuretic effect. V. viride does not inhibit sympathetic vasoconstrictor responses as evidenced by the maintenance of vasopressor overshoots, skin temp. levels, vascular reflexes in the digits, the cold pressor response, and postural adaptation. During the period of reduced arterial pressure, blood flow and vascular distensibility in sympathectomized as compared with normally innervated extremities do not increase, indicating that part of the vascular response in the limbs may be mediated over sympathetic nervous pathways possibly through sympathetic vasodilator fibers. Epinephrine and ephedrine reverse the hypotensive effects of Veratrum.