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

Objective: 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. Study Design: 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. Results: 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. Conclusion: The results of this study support the existence of venoarterial communication within the uterine circulation through an endothelin-1–sensitive pathway. (Am J Obstet Gynecol 2002;187:1653-9.)