Atropine Influence on Altered Hemodynamics of the Primate Kidney in Hemorrhagic Shock 1

Abstract

Summary

Atropine sulfate was infused intra-aortically (0.275 mg/kg/min) to attempt blockade of medullary cholinergic fibers which might function during hemorrhagic shock to promote washout of the medullary gradient of osmolality by maintaining MBF. It was found that infusion of atropine in the dosage used and by the route described, resulted in relative increase in C _PAH and C _In over the trend observed in a group of untreated animals, similarly subjected to hemorrhagic hypotension, with no change in FF. Results could be explained by blockade of preganglionic (aorticorenal) cholinergic fibers, resulting in reduction of postganglionic adrenergic vasoconstrictor influences on afferent arterioles. No influence of atropine could be detected on urine vollume sodium clearance, and osmolar clearance when expressed as a fraction of C _In, nor on U/P osmolality. If intrarenal cholinergic fibers were blocked, the expected results of this (increase in FF and reduced total RBF) were covered up by the more marked influence resulting from diminution of enhanced vasoconstrictor activity.