Effect of diadenosine phosphates on human umbilical vessels: novel platelet‐derived vasoconstrictors.

Abstract

The responses of human isolated umbilical artery to the novel platelet‐ derived mediators, diadenosine phosphates, P1,P5‐di(adenosine‐ 5′)pentaphosphate (AP5A) and P1,P6‐di(adenosine‐5′)hexaphosphate (AP6A) were studied in vitro. AP5A (1 nM‐300 microM; n = 7) and AP6A (1 nM‐30 microM; n = 5) produced transient concentration‐dependent contractions. Responses to AP5A were unaffected by co‐incubation with indomethacin (10 microM; n = 4), NGmonomethyl‐L‐arginine (L‐NMMA; 300 microM; n = 4) and theophylline (1 microM; n = 5). These results demonstrate that diadenosine phosphates have constrictor effects on human blood vessels in vitro and are consistent with a role for these platelet‐derived mediators in the regulation of blood vessel tone. Copyright © 1995, Wiley Blackwell. All rights reserved