title: P2Y(1) receptor activation enhances the rate of rat pinealocyte-induced extracellular acidification via a calcium-dependent mechanism.
abstract: Pineal gland G-protein coupled P2Y(1) receptors potentiate noradrenaline-induced N'-acetylserotonin production, a long term response which occurs after 5 h incubation. In the current study we show that a short-term effect of stimulation of P2Y(1) receptors is the increase in extracellular acidification rate (ECAR), which is mediated by an increase in intracellular calcium concentration ([Ca(2+)](i)). The pD(2) values for ATP (3.06 +/- 0.12)-induced ECAR increase was significantly smaller (p < 0.01) than that for ADP (3.64 +/- 0.18), 2MeSATP (3.56 +/- 0.02) and 2MeSADP (3.65 +/- 0.13). The selective P2Y(1) receptor antagonists A3'P-5'P and A3'P-5'PS inhibited the increase in ECAR-induced by ADP. Clamping [Ca(2+)](i) with BAPTA (30 and 50 micromol/l) led to inhibition of ADP-induced increase in ECAR. Agonist and antagonist data indicate P2Y(1) activation leads to a [Ca(2+)](i)-dependent acidification of the extracellular medium.
authors.affiliation: Department of Physiology, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil.
authors.forename: Zulma Silva
authors.initials: ZS
authors.lastname: Ferreira
authors.forename: Célia Regina S
authors.initials: CR
authors.lastname: Garcia
authors.forename: David C
authors.initials: DC
authors.lastname: Spray
authors.forename: Regina P
authors.initials: RP
authors.lastname: Markus
mesh_terms: D000244:Adenosine Diphosphate / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000037:antagonists & inhibitors / Q000378:metabolism; D004533:Egtazic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D045604:Extracellular Fluid / Q000737:chemistry*; D005260:Female; D019204:GTP-Binding Proteins / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008297:Male; D010870:Pineal Gland / Q000166:cytology* / Q000378:metabolism*; D058919:Purinergic P2 Receptor Antagonists; D051381:Rats; D017208:Rats, Wistar; D018048:Receptors, Purinergic P2 / Q000378:metabolism*; D058472:Receptors, Purinergic P2Y1
chemical_list: C546384:P2ry1 protein, rat; D058919:Purinergic P2 Receptor Antagonists; D018048:Receptors, Purinergic P2; D058472:Receptors, Purinergic P2Y1; D004533:Egtazic Acid; D000244:Adenosine Diphosphate; D019204:GTP-Binding Proteins; C025603:1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid; D002118:Calcium