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

Abstract

αβmeATP-evoked concentration-dependent, PPADS-sensitive, desensitising, P2X receptor-mediated, constrictions of mesenteric, basilar and septal artery rings with EC₅₀ values of 1, 1 and 30 μM, respectively. In patch clamp studies on acutely dissociated artery smooth cells αβmeATP-evoked transient inward currents (τ∼100 ms) with mean current densities of ∼340, 175 and 120 pA/pF, respectively. P2X₁ 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 P2X₁ receptor immunoreactivity was not detected in septal arteries and the αβmeATP sensitivity of constriction was not consistent with the involvement of P2X₁ receptors. These results suggest that not all arteries share a common P2X receptor phenotype.