title: In vitro characterization of acid secretion in the gilthead sea bream (Sparus aurata) stomach.
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.
authors.affiliation: Núcleo de Investigación en Producción Alimentaria/Escuela de Acuicultura, Facultad de Recursos Naturales, Universidad Católica de Temuco, Avda. Rudecindo Ortega 02950, PO Box 15-D, Temuco, Chile. Electronic address: marquez.lorenzo728@gmail.com.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Márquez
authors.forename: Juan
authors.initials: J
authors.lastname: Fuentes
mesh_terms: D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D000818:Animals; D002217:Carbachol / Q000494:pharmacology; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism; D017097:Electric Impedance; D005682:Gadolinium / Q000494:pharmacology; D005744:Gastric Acid / Q000378:metabolism*; D005753:Gastric Mucosa / Q000187:drug effects / Q000502:physiology; D066298:In Vitro Techniques; D018942:Macrolides / Q000494:pharmacology; D018721:Muscarinic Agonists / Q000494:pharmacology; D009853:Omeprazole / Q000494:pharmacology; D054328:Proton Pump Inhibitors / Q000494:pharmacology; D044169:Receptors, Calcium-Sensing / Q000819:agonists / Q000378:metabolism; D021541:Sea Bream / Q000378:metabolism*
chemical_list: D018942:Macrolides; D018721:Muscarinic Agonists; D054328:Proton Pump Inhibitors; D044169:Receptors, Calcium-Sensing; D005576:Colforsin; C040929:bafilomycin A1; D002217:Carbachol; D005682:Gadolinium; D000242:Cyclic AMP; D009853:Omeprazole; D015056:1-Methyl-3-isobutylxanthine
keywords: Calcium-sensing receptor agonists; Gastric acid secretion; HK-ATPase; Muscarinic agonists; Sparus aurata; V-ATPase; cAMP promoters