Vasopressin Vascular and Reflex Effects–A Theoretical Analysis

Abstract

Publisher Summary This chapter describes the role of vasopressin (AVP) in cardiovascular function and presents evidence for the (1) participation of AVP in the short-term regulation of arterial pressure by its direct vascular actions and (2) AVP interaction with the central nervous system baroreceptor reflex pathways. The chapter suggests that most of the arterial pressure regulation with AVP infusion can be explained by reflex control of venous compliance or unstressed volume. The extent to which cardiac output is altered by AVP is dependent on the relative degree of arterial vasoconstriction between the compliant and non-compliant parallel flow beds. However, not all of the observed actions of AVP are accounted for, particularly, the predicted rise in total peripheral resistance (TPR) is less than that seen in normal animals with comparable AVP concentrations. It appears that some mechanism exists, whereby the reflex buffering of arterial resistance with AVP infusion is attenuated so that TPR rises to a higher level than would be predicted if the baroreceptors are attempting to offset the rise in resistance. While, equations are found, which could predict such behavior, they differ significantly from the classical single set point control theory and go beyond the present understanding of the autonomic nervous system.