In vitro characterization of acid secretion in the gilthead sea bream (Sparus aurata) stomach

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Autor:
Márquez Rodríguez, Lorenzo - Fuentes, Juan
URI:
http://repositoriodigital.uct.cl/handle/10925/2963
Datos de publicación:
COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY A-MOLECULAR & INTEGRATIVE PHYSIOLOGY,Vol.167,52-58,2014
Temas:
Calcium-sensing receptor agonists - cAMP promoters - Gastric acid secretion - HK-ATPase - Muscarinic agonists - Sparus aurata - V-ATPase
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Resumen:
The gastric acid secretion of juvenile Sparus aurata was characterized in Ussing chambers; secretion rates were determined by a pH-stat method at pH 5.50 and bioelectrical parameters were measured in current-clamped tissues. The basal secretion equaled to 535 +/- 87 nmol.cm(-2).h(-1). Serosal carbachol 100 mu M produced an increase (Delta J(H+)) of 725 +/- 133 nmol.cm(-2).h(-1) from basal secretion, this effect being inhibited by mucosal omeprazole 100 mu M. Basal secretion was also sensitive to the combination of serosal forskolin (FK) 10 mu M + serosal isobutylmethylxanthine (IBMX) 100 mu M (Delta J(H+) = 793 +/- 239 nmol.cm(-2).h(-1)); this effect was insensitive to mucosa( omeprazole 100 mM but inhibited by mucosal bafilomycin A1 100 nM. The effect of carbachol proceeded within a few minutes (<10 min), whereas the effect of FK + IBMX was gradual, taking 40 min to reach the maximum. The addition of mucosal gadolinium (Gd3+) 100 mu M, a potent calcium-sensing receptor (CaR) agonist, stimulated the basal secretion (Delta J(H+) = 340 +/- 81 nmol.cm(-2).h(-1)). The present results indicate that the add secretion mechanism in the sea bream stomach is regulated by muscarinic and CaR-like receptors, cAMP is implicated in the signal transduction, and at least two proton pumps, a HK-ATPase and a V-ATPase contribute to acid secretion. (C) 2013 Elsevier Inc. All rights reserved.

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