Intracellular free calcium concentrations in isolated pancreatic acini; effects of secretagogues.
Isolated pancreatic acini were loaded with the calcium selective fluorescent indicator, quin-2. Measurements of cellular K+ content and lactic dehydrogenase release indicated that cell viability was not affected by quin-2 loading. The concentration of intracellular free calcium of unstimulated acinar cells was calculated to be 180 +/- 4 nM. When cells suspended in media containing millimolar calcium were exposed to the secretagogues carbachol and cholecystokinin a rapid increase in [Ca2+]i occurred. Both the amplitude and rate of rise of the concentration increase were dose dependent with [Ca2+]i reaching a maximum of 860 +/- 41 nM. The dose-response relationship coincides with the known concentration dependence of the stimulation of amylase release by these agents. In the absence of extracellular calcium, carbachol was still able to elicit a rise in [Ca2+]i. These studies indicate that pancreatic secretagogues induce an increase in [Ca2+]i of acinar cells, both in the presence or absence of extracellular calcium.
D000634:Aminoquinolines; D000681:Amylases / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002217:Carbachol / Q000494:pharmacology; D002766:Cholecystokinin / Q000494:pharmacology; D005456:Fluorescent Dyes; D066298:In Vitro Techniques; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008297:Male; D051379:Mice; D010179:Pancreas / Q000187:drug effects / Q000378:metabolism*; D011188:Potassium / Q000378:metabolism
D000634:Aminoquinolines; D005456:Fluorescent Dyes; D002217:Carbachol; D002766:Cholecystokinin; D007770:L-Lactate Dehydrogenase; D000681:Amylases; C035739:Quin2; D011188:Potassium; D002118:Calcium