In vitro characterization of acid secretion in the gilthead sea bream (Sparus aurata) stomach
In vitro characterization of acid secretion in the gilthead sea bream (Sparus aurata) stomach
Authors
Márquez Rodríguez, Lorenzo
Fuentes, Juan
Fuentes, Juan
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Date
Datos de publicación:
10.1016/j.cbpa.2013.10.016
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Abstract
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.