P2Y receptor subtypes differentially couple to inwardly-rectifying potassium channels

Abstract

Subtypes of P2Y receptors are well characterized with respect to their agonist profile but little is known about differences in their intracellular signalling properties. When expressed in Xenopus oocytes, both P2Y2 and P2Y6 receptors effectively couple to endogenous Ca2+-dependent Cl--channels. However, only P2Y2 receptors increased currents mediated by inward-rectifier K+ channels of the Kir3.0 subfamily. This increase in Kir-current was sensitive to pertussis toxin, while activation of Ca2+-dependent Cl--channels was not. In contrast, suramin, a P2 receptor antagonist, inhibited activation of both channels. These observations suggest that, in contrast to P2Y6, P2Y2 receptors couple to two different classes of G proteins.