P2Y12 Receptor Localizes in the Renal Collecting Duct and Its Blockade Augments Arginine Vasopressin Action and Alleviates Nephrogenic Diabetes Insipidus

P2Y(12) receptor (P2Y(12)-R) signaling is mediated through G, ultimately reducing cellular cAMP levels. Because cAMP is a central modulator of arginine vasopressin (AVP)-induced water transport in the renal collecting duct (CD), we hypothesized that if expressed in the CD, P2Y(12)-R may play a role in renal handling of water in health and in nephrogenic diabetes insipidus. We found P2Y(12)-R m RNA expression in rat kidney, and immunolocalized its protein and aquaporin-2 (AQP2) in CD principal cells. Administration of clopidogrel bisulfate, an irreversible inhibitor of P2Y(12)-R, significantly increased urine concentration and AQP2 protein in the kidneys of Sprague Dawley rats. Notably, clopidogrel did not alter urine concentration in Brattleboro rats that lack AVP. Clopidogrel administration also significantly ameliorated lithium-induced polyuria, improved urine concentrating ability and AQP2 protein abundance, and reversed the lithium-induced increase in freewater excretion, without decreasing blood or kidney tissue lithium levels. Clopidogrel administration also augmented the lithium-induced increase in urinary AVP excretion and suppressed the lithium-induced increase in urinary nitrates/nitrites (nitric oxide production) and 8-isoprostane (oxidative stress). Furthermore, selective blockade of P2Y(12)-R bythe reversible antagonist PSB-0739 in primary cultures of rat inner medullary CD cells potentiated the expression of AQP2 and AQF,'3 mRNA, and cAMP production induced by dDAVP (desmopressin). In conclusion, pharnnacologic blockade of renal P262-R increases urinary concentrating ability by augmenting the effect of AVP on the kidney and ameliorates lithium-induced N DI by potentiating the action of AVP on the CD. This strategy may offer a novel and effective therapy for lithium-induced NDI.