Effects of intracoronary infusion of the vasoactive intestinal peptide antagonist [4Cl-D-Phe6-Leu17]VIP in the awake dog

Abstract

Intracoronary infusion of [4Cl-D-Phe6-Leu17]VIP caused modest significant inhibition of the coronary vasodilation produced by intraarterial VIP, but did not significantly inhibit serotonin-induced coronary vasodilation. In addition, infusion of [4Cl-D-Phe6-Leu17]VIP did not result in significant changes in baseline coronary resistance, heart rate or left ventricular dP/dt. These findings demonstrate that [4Cl-D-Phe6-Leu17]VIP is a competitive antagonist of VIP-induced vasodilation in the canine coronary circulation, but fail to demonstrate a significant role for VIP in the regulation of resting coronary vasomotor tone, and do not support the hypothesis that VIP is a mediator of serotonin-induced coronary arteriolar dilation.