Comparison of P2X receptors in rat mesenteric, basilar and septal (coronary) arteries.

alpha beta meATP-evoked concentration-dependent, PPADS-sensitive, desensitising, P2X receptor-mediated, constrictions of mesenteric, basilar and septal artery rings with EC(50) values of 1, 1 and 30 microM, respectively. In patch clamp studies on acutely dissociated artery smooth cells alpha beta meATP-evoked transient inward currents (tau approximately 100 ms) with mean current densities of approximately 340, 175 and 120 pA/pF, respectively. P2X(1) receptor immunoreactivity was expressed in mesenteric and basilar arteries and this receptor subunit appears to dominate the P2X receptor phenotype in these vessels. In contrast P2X(1) receptor immunoreactivity was not detected in septal arteries and the alpha beta meATP sensitivity of constriction was not consistent with the involvement of P2X(1) receptors. These results suggest that not all arteries share a common P2X receptor phenotype.