Effects of denervation and vasoactive agents on vascular pressures and weight of dog forelimb

Abstract

The dog forelimb was locally denervated and vasoactive agents infused into the brachial artery at rates having little effect upon large vessel pressures. Forelimb weight and small and large arterial and venous pressures were frequently recorded. Because the limb was in a dependent position, it gained weight at a diminishing rate. Denervation increased small venous pressure and the rate of weight gain. Angiotensin and vasopressin decreased small venous pressure and the rate of weight gain. Methacholine, serotonin and histamine each increased small venous pressure and the rate of weight gain. Levarterenol decreased, did not change or increased, both small venous pressure and rate of weight gain. These findings, when combined with previously reported effects upon arterial and venous resistances, indicate that local denervation and local administration of vasoactive agents vary the transfer of water across the capillary membrane by changing capillary hydrostatic pressure and emphasize the importance of the ratio of arterial to venous resistances in determining capillary hydrostatic pressure and, hence, water storage in tissues.