Arginine vasopressin stimulates H -ATPase in MDCK cells via V1 (cell Ca ) and V2 (cAMP) receptors

Oliveira-Souza, Maria, Raif Musa-Aziz, Gerhard Malnic, and Margarida de Mello Aires. Arginine vasopressin stimulates H ATPase in MDCK cells via V1 (cell Ca ) and V2 (cAMP) receptors. Am J Physiol Renal Physiol 286: F402–F408, 2004. First published September 9, 2003; 10.1152/ajprenal.00121.2003.—The effect of arginine vasopressin (AVP) and/or atrial natriuretic peptide (ANP) on the regulation of intracellular pH (pHi) via H -ATPase and of cytosolic calcium ([Ca ]i) was investigated in Madin-Darby canine kidney (MDCK) cells by the fluorescent probes BCECF-AM and fluo-4-AM, respectively. The pHi recovery rate was examined after intracellular acidification following an NH4Cl pulse, in the presence of zero Na plus Schering 28080 (a specific inhibitor of H -K ATPase). AVP (10 -10 6 M) increased the rate of pHi recovery and [Ca ]i in a dose-dependent manner. V1or V2-receptor antagonists impaired the effect of AVP on both processes, and DDAVP (10 10 6 M; a V2-selective agonist) caused a dose-dependent stimulation of them. [Ca ]i or cAMP (as increased by 10 5 M thapsigargin or 8-BrcAMP, respectively) alone had no effect on H -ATPase, but their synergic action was necessary to stimulate H -ATPase. In agreement with these findings, ANP (10 6 M) or dimethyl-BAPTA-AM (5 10 5 M), impairing the increase of [Ca ]i in response to AVP, blocks the stimulatory effect of AVP on H -ATPase.