Calcium mediates gastrin-induced gastric histamine release in the rat.
This study examined the second messenger system responsible for gastrin-induced histamine release from the rat stomach. We examined the effect of different concentrations of ionized calcium, the calcium-channel blockers verapamil and nicardipine, and the intracellular calcium-chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid/acetoxymethyl ester (BAPTA/AM) on gastrin-stimulated histamine release in the totally isolated vascularly perfused rat stomach. Moreover, the effect on baseline histamine release of caffeine as well as of forskolin and 3-isobutyl-1-methylxanthine (IBMX) was tested. Gastrin induced an immediate 10- to 15-fold increase in venous histamine. Perfusate ionized calcium in the 0.25-1.25 mM range did not affect histamine release; histamine release was attenuated by the 0.00 and 1.75 mM calcium concentrations. Verapamil, nicardipine, and BAPTA/AM inhibited gastrin-stimulated histamine release. Caffeine stimulated the release, whereas forskolin and IBMX had no effect. We conclude that gastrin-induced histamine release from the rat stomach is mediated by calcium, probably both from the intracellular pool and by transmembrane flux from the extracellular space.
Sandvik
A K
AK
Department of Medicine, University Hospital, Trondheim, Norway.
Brenna
E
E
Waldum
H L
HL
D000818:Animals; D002118:Calcium / Q000494:pharmacology / Q000502:physiology*; D000242:Cyclic AMP / Q000378:metabolism; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D005753:Gastric Mucosa / Q000378:metabolism*; D005755:Gastrins / Q000494:pharmacology*; D006636:Histamine Release / Q000502:physiology*; D008297:Male; D009529:Nicardipine / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D014700:Verapamil / Q000494:pharmacology
D005755:Gastrins; C070379:1,2-bis(2-aminophenoxy)ethane N,N,N',N'-tetraacetic acid acetoxymethyl ester; D004533:Egtazic Acid; D014700:Verapamil; D009529:Nicardipine; D000242:Cyclic AMP; D002118:Calcium