title: Extracellular acidification related to the stimulation of catecholamines release by strontium in the bovine adrenal medulla.
abstract: The possible modifications of extracellular pH associated with the secretion of catecholamines evoked by the introduction of 2.2 mM Sr2+ to a Ca(2+)-free, buffer-free, Locke solution were investigated in decorticated perfused bovine adrenal glands. A progressive and reversible decrease of external pH accompanied the catecholamine release promoted by Sr(2+)-introduction into the perfusion fluid. This extracellular acid shift was practically undetected when the chromaffin tissue was stimulated by the addition of Sr2+ to a buffered medium. Both the secretory response as well as the extracellular pH drop mediated by Sr(2+)-introduction to a Ca(2+)-free, buffer-free, Locke solution were markedly inhibited by methoxyverapamil (0.3 mM), Mg2+ (20 mM) and hyperosmolarity (750 mOsm). The exposure of the adrenal medulla to a Ca(2+)-free, buffer-free, high-K+ solution containing 2.2 mM Sr2+ for 6 min promoted a significant enhancement of both the secretory response and the acidification of the perfusates compared with the responses evoked by Sr2+ in a 5.6 mM K+ medium. These results are consistent with the existence of a close relationship between extracellular acidification and the release of catecholamines triggered by the introduction of Sr2+ to the perfusion fluid.
authors.affiliation: Departamento de Fisiología, Facultad de Medicina, Universidad de Buenos Aires, Argentina.
authors.forename: P N
authors.initials: PN
authors.lastname: Viglione
authors.forename: K
authors.initials: K
authors.lastname: Pereyra
authors.forename: C F
authors.initials: CF
authors.lastname: Reyes-Toso
authors.forename: J E
authors.initials: JE
authors.lastname: Pinto
mesh_terms: D000313:Adrenal Medulla / Q000187:drug effects* / Q000378:metabolism; D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002395:Catecholamines / Q000378:metabolism*; D002417:Cattle; D005110:Extracellular Space / Q000378:metabolism*; D005711:Gallopamil / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D008274:Magnesium / Q000378:metabolism; D009994:Osmolar Concentration; D011188:Potassium / Q000378:metabolism; D013324:Strontium / Q000494:pharmacology*
chemical_list: D002121:Calcium Channel Blockers; D002395:Catecholamines; D005711:Gallopamil; D008274:Magnesium; D011188:Potassium; D013324:Strontium