Selective ligand-induced intracellular calcium changes in a population of rat isolated gastric endocrine cells.
OBJECTIVE
Peripheral regulation of acid secretion depends mainly on stimulation or inhibition of the three major gastric endocrine cells (enterochromaffin-like, gastrin, and somatostatin). The aim of this paper was to define physiological responses of enterochromaffin-like, gastrin, and somatostatin cells in a mixed endocrine cell population by measuring ligand-selective changes of intracellular calcium ([Ca2+]i) in individual cells.


METHODS
Endocrine cells were enriched from a rat gastric cell suspension by elutriation, a density-gradient fractionation, and a 48-hour short-term culture. [Ca2+]i responses of individual cells to various ligands such as gastrin/carboxy-terminal cholecystokinin octapeptide and selective cholecystokinin antagonists, carbachol, and gastrin-releasing peptide were monitored using video imaging in a perfusion chamber. Characteristic [Ca2+]i changes distinguished the three cell types, confirmed by immunostaining.


RESULTS
All enterochromaffin-like cells respond to cholecystokinin-B receptor stimulation, but only a few respond to carbachol. Gastrin cells respond to both gastrin-releasing peptide and carbachol but not to cholecystokinin-receptor agonists. Somatostatin cells have both stimulatory cholecystokinin-A and cholecystokinin-B receptors and inhibitory muscarinic receptors. All cells have inhibitory somatostatin receptors.


CONCLUSIONS
Calcium-signaling responses of gastric endocrine cells are distinctive. This allows individual cell types in a mixed population to be characterized and permits an analysis of the hormones and transmitters that act directly on a specific cell type.
Zeng
N
N
Department of Physiology and Medicine, UCLA, USA.
Walsh
J H
JH
Kang
T
T
Helander
K G
KG
Helander
H F
HF
Sachs
G
G
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002838:Chromaffin System / Q000166:cytology / Q000378:metabolism; D004702:Endocrine Glands / Q000166:cytology / Q000378:metabolism*; D005260:Female; D005753:Gastric Mucosa / Q000378:metabolism*; D007425:Intracellular Membranes / Q000378:metabolism*; D008024:Ligands; D051381:Rats; D017207:Rats, Sprague-Dawley; D018004:Receptors, Bombesin / Q000378:metabolism; D011949:Receptors, Cholecystokinin / Q000378:metabolism; D011976:Receptors, Muscarinic / Q000378:metabolism; D017481:Receptors, Somatostatin / Q000378:metabolism; D013270:Stomach / Q000166:cytology
D008024:Ligands; D018004:Receptors, Bombesin; D011949:Receptors, Cholecystokinin; D011976:Receptors, Muscarinic; D017481:Receptors, Somatostatin; D002118:Calcium