Basolateral, but not apical, ATP inhibits vasopressin action in rat inner medullary collecting duct

Previous studies have shown that basolateral ATP inhibits vasopressin action in the renal collecting tubule. Although there is evidence for an apical P2Y(2) receptor in this tubule segment, it is not known whether apical ATP has similar effects. In the rat inner medullary collecting duct basolateral, but not apical, ATP (0.1-100 muM) reversibly inhibited vasopressin-induced increases in water permeability, with an IC50 of 1.09 muM. Basolateral UTP. but not ADP, alpha,beta-methylene-ATP or 2-methylthio-ATP also inhibited vasopressin action. It is concluded that basolateral but not apical P2Y(2) receptors inhibit vasopressin action in the collecting duct. (C) 2002 Elsevier Science B.V. All rights reserved.