Venoarterial communication as a mechanism for localized signaling in the rat uterine circulation.

Abstract

Venoarterial communication describes the phenomenon whereby molecular signals in a vein directly influence an adjacent artery. The objective of this study was to investigate, in vitro, the existence of such a pathway in the uterine circulation of the rat. Paired uterine vessels from late pregnant and virgin rats were pressurized and studied in a dual-perfusion vasograph. Veins were perfused with phenylephrine and endothelin-1, alone or in combination, and the vasoactive responses of both vessels were recorded. Venous perfusion of phenylephrine resulted in concentration-dependent arterial, but not venous, constriction. Conversely, veins, but not arteries, demonstrated concentration-dependent constriction to intravenous endothelin-1. Superfusion of endothelin-1 constricted both vessels. Coperfusion of endothelin-1 and phenylephrine constricted the veins and attenuated the previously observed arterial response to intravenous phenylephrine. The results of this study support the existence of venoarterial communication within the uterine circulation through an endothelin-1-sensitive pathway.