AJP - Gastrointestinal and Liver Physiology, Vol 273, Issue 2 281-G288, Copyright © 1997 by American Physiological Society

ARTICLES

L-type calcium channels regulate gastrin release from human antral G cells

J. M. Ray, P. E. Squires, R. M. Meloche, D. W. Nelson, T. P. Snutch and A. M. Buchan
Department of Physiology, University of British Columbia, Vancouver, Canada.

In mRNA samples isolated from a gastrin (G) cell-enriched human antral cell preparation, reverse transcription-polymerase chain reaction identified products encoding part of the alpha 1-subunit of class C and D L-type voltage-dependent Ca2+ channels (VDCCs). Analysis of the polymerase chain reaction products demonstrated a 100% homology with the known human gene sequences. An antibody to the class D alpha 1-subunit immunostained 30-40% of the cultured cells; of these 90% were gastrin immunoreactive. Gastrin release stimulated by terbutaline (beta 2-agonist) and forskolin was abolished by blockade of L-type VDCCs; the effect of 3.6 mM extracellular Ca2+ was only partially reversed. In G cells the rise in intracellular Ca2+ observed in response to increasing extracellular Ca2+ from 0.5 to 3.6 mM was reduced by nitrendipine. These results indicated that human antral cells expressed class C and D L-type VDCCs. Activation of G cells with beta-adrenergic agonists required an influx of extracellular Ca2+ through these channels to stimulate gastrin release. However, activation of L-type channels was not the only mechanism underlying Ca(2+)-stimulated gastrin release.

This article has been cited by other articles:

				P. E. Squires, R. M. Meloche, and A. M. J. Buchan Bombesin-evoked gastrin release and calcium signaling in human antral G cells in culture Am J Physiol Gastrointest Liver Physiol, January 1, 1999; 276(1): G227 - G237. [Abstract] [Full Text] [PDF]