Gastrin-stimulated changes in Ca2+ concentration in parietal cells depends on adenosine 3',5'-cyclic monophosphate levels.
OBJECTIVE
The parietal cell has secretory receptors for histamine and acetylcholine, whereas the functional nature of the gastrin/cholecystokinin B receptor is controversial. This study in isolated gastric glands investigates the cholecystokinin B receptor-induced intracellular calcium concentration ([Ca]i) response in enterochromaffin-like (ECL) and parietal cells as a function of adenosine 3',5'-cyclic monophosphate pathways.


METHODS
The responses of [Ca]i in ECL and parietal cells of perfused rabbit or rat calcium orange-loaded gastric glands were determined using confocal microscopy. ECL cells were identified by position, size, and autofluorescence and parietal cells by position and size.


RESULTS
Gastrin (1 mumol/L) produced an elevation of [Ca]i levels in both ECL and parietal cells. In the presence of 100 mumol/L cimetidine, the ECL cell response to gastrin was not affected but the [Ca]i response of the parietal cell was abolished. With dibutyryl adenosine 3',5' phosphate in addition to cimetidine, the response of the parietal cell [Ca]i to gastrin was restored in both the rat and rabbit.


CONCLUSIONS
The [Ca]i response of the parietal but not the ECL cell to the addition of gastrin seems to depend on the presence of normal or elevated intracellular adenosine 3',5'-cyclic monophosphate levels. Therefore, H2 receptor activity may be permissive for the effect of gastrin on parietal cell function.
Geibel
J
J
Department of Surgery, Yale University, New Haven, Connecticut, USA.
Abraham
R
R
Modlin
I
I
Sachs
G
G
D000818:Animals; D003994:Bucladesine / Q000494:pharmacology; D002118:Calcium / Q000032:analysis*; D002927:Cimetidine / Q000494:pharmacology; D000242:Cyclic AMP / Q000032:analysis*; D004759:Enterochromaffin Cells / Q000737:chemistry; D005755:Gastrins / Q000494:pharmacology*; D066298:In Vitro Techniques; D018613:Microscopy, Confocal; D010295:Parietal Cells, Gastric / Q000737:chemistry*; D011817:Rabbits; D051381:Rats; D017207:Rats, Sprague-Dawley
D005755:Gastrins; D003994:Bucladesine; D002927:Cimetidine; D000242:Cyclic AMP; D002118:Calcium