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

Comp Biochem Physiol A Mol Integr Physiol. 2014 Jan:167:52-8. doi: 10.1016/j.cbpa.2013.10.016. Epub 2013 Oct 12.

Abstract

The gastric acid secretion of juvenile Sparus aurata was characterized in Ussing chambers; secretion rates were determined by a pH-stat method at pH5.50 and bioelectrical parameters were measured in current-clamped tissues. The basal secretion equaled to 535±87nmol·cm(-2)·h(-1). Serosal carbachol 100μM produced an increase (ΔJH(+)) of 725±133nmol·cm(-2)·h(-1) from basal secretion, this effect being inhibited by mucosal omeprazole 100μM. Basal secretion was also sensitive to the combination of serosal forskolin (FK) 10μM+serosal isobutylmethylxanthine (IBMX) 100μM (ΔJH(+)=793±239nmol·cm(-2)·h(-1)); this effect was insensitive to mucosal omeprazole 100mM but inhibited by mucosal bafilomycin A1 100nM. The effect of carbachol proceeded within a few minutes (<10min), whereas the effect of FK+IBMX was gradual, taking 40min to reach the maximum. The addition of mucosal gadolinium (Gd(3+)) 100μM, a potent calcium-sensing receptor (CaR) agonist, stimulated the basal secretion (ΔJH(+)=340±81nmol·cm(-2)·h(-1)). The present results indicate that the acid 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.

Keywords: Calcium-sensing receptor agonists; Gastric acid secretion; HK-ATPase; Muscarinic agonists; Sparus aurata; V-ATPase; cAMP promoters.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 1-Methyl-3-isobutylxanthine / pharmacology
  • Animals
  • Carbachol / pharmacology
  • Colforsin / pharmacology
  • Cyclic AMP / metabolism
  • Electric Impedance
  • Gadolinium / pharmacology
  • Gastric Acid / metabolism*
  • Gastric Mucosa / drug effects
  • Gastric Mucosa / physiology
  • In Vitro Techniques
  • Macrolides / pharmacology
  • Muscarinic Agonists / pharmacology
  • Omeprazole / pharmacology
  • Proton Pump Inhibitors / pharmacology
  • Receptors, Calcium-Sensing / agonists
  • Receptors, Calcium-Sensing / metabolism
  • Sea Bream / metabolism*

Substances

  • Macrolides
  • Muscarinic Agonists
  • Proton Pump Inhibitors
  • Receptors, Calcium-Sensing
  • Colforsin
  • bafilomycin A1
  • Carbachol
  • Gadolinium
  • Cyclic AMP
  • Omeprazole
  • 1-Methyl-3-isobutylxanthine