AJP - Gastrointestinal and Liver Physiology, Vol 264, Issue 1 51-G56, Copyright © 1993 by American Physiological Society
Calcium mediates gastrin-induced gastric histamine release in the rat
A. K. Sandvik, E. Brenna and H. L. Waldum
Department of Medicine, University Hospital, Trondheim, Norway.
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.
