title: Arginine-vasopressin modulates intracellular pH via V1 and V2 receptors in renal collecting duct cells.
abstract: Arginine-vasopressin (AVP) has been proposed to be involved in the modulation of acid-base transporters; however, the nature of the mechanisms underlying AVP direct action on intracellular pH (pH(i)) in the cortical collecting duct (CCD) is not yet clearly defined. The aim of the present study was to elucidate which are the proteins implicated in AVP modulation of pH(i), as well as the receptors involved in these responses using a CCD cell line (RCCD(1)); pH(i) was monitored with the fluorescent dye BCECF in basal conditions and after stimulation with basolateral 10(-8) M AVP. Specific V1- or V2-receptor antagonists were also used. RT-PCR studies demonstrated that RCCD(1) cells express V1a and V2 receptors. Functional studies showed that while V2-receptor activation induced a biphasic response (alkalinization-acidification), V1-receptor activation resulted in an intracellular acidification. The V2-mediated alkalinization phase involves the activation of basolateral NHE-1 isoform of the Na(+)/H(+) exchanger while in the acidification phase CFTR is probably implicated. On the other hand, V1-mediated acidification was due to activation of a Cl(-)/HCO(3)(-) exchanger. We conclude that in RCCD(1) cells AVP selectively activates, via a complex of V1 and V2 receptor-mediated actions, different ion transporters linked to pH(i) regulation which might have physiological implications.
authors.affiliation: Laboratorio de Biomembranas, Departamento de Fisiología y Biofísica, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina.
authors.forename: Valeria
authors.initials: V
authors.lastname: Rivarola
authors.forename: Paula
authors.initials: P
authors.lastname: Ford
authors.forename: María
authors.initials: M
authors.lastname: del Pilar Flamenco
authors.forename: Luciano
authors.initials: L
authors.lastname: Galizia
authors.forename: Claudia
authors.initials: C
authors.lastname: Capurro
mesh_terms: D000818:Animals; D065092:Antidiuretic Hormone Receptor Antagonists; D001127:Arginine Vasopressin / Q000494:pharmacology*; D002460:Cell Line; D027963:Chloride-Bicarbonate Antiporters / Q000378:metabolism; D005786:Gene Expression Regulation; D006863:Hydrogen-Ion Concentration; D007685:Kidney Tubules, Collecting / Q000187:drug effects* / Q000378:metabolism*; D051381:Rats; D017483:Receptors, Vasopressin / Q000235:genetics / Q000378:metabolism*; D017923:Sodium-Hydrogen Exchangers / Q000378:metabolism
chemical_list: D065092:Antidiuretic Hormone Receptor Antagonists; D027963:Chloride-Bicarbonate Antiporters; D017483:Receptors, Vasopressin; D017923:Sodium-Hydrogen Exchangers; D001127:Arginine Vasopressin