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

alpha beta meATP-evoked concentration-dependent, PPADS-sensitive, desensiti sing, P2X receptor-mediated, constrictions of mesenteric, basilar and septa l artery rings with EC50 values of 1, 1 and 30 mu M, respectively. In patch clamp studies on acutely dissociated artery smooth cells alpha beta meATP- evoked transient inward currents (tau similar to 100 ms) with mean current densities of similar to 340, 175 and 120 pA/pF, respectively. P2X(1) recept or immunoreactivity was expressed in mesenteric and basilar arteries and th is 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 no t consistent with the involvement of P2X(1) receptors. These results sugges t that not all arteries share a common P2X receptor phenotype. (C) 2000 Els evier Science B.V. All rights reserved.