Acetylcholine and cholecystokinin induce different patterns of oscillating calcium signals in pancreatic acinar cells.
Receptor-activated cytoplasmic calcium (Ca2+) oscillations have been investigated in single pancreatic acinar cells by microfluorimetry (Fura-2 as indicator). At submaximal concentrations of the agonists acetylcholine (ACh) and cholecystokinin octapeptide (CCK-8), both give rise to oscillatory changes in the cytosolic free calcium concentration ([Ca2+]i). The patterns of oscillations are markedly and consistently different for each of these two agonists. The ACh induced oscillations are superimposed upon a median elevation in background [Ca2+]i. The CCK-8 induced oscillations are of longer duration with [Ca2+]i returning to prestimulus levels between the discrete spikes. The ACh induced oscillations are rapidly abolished upon removal of extracellular Ca2+ while the CCK-8 induced oscillations persist for many minutes in the absence of external Ca2+. The CCK-8, but not the ACh, induced oscillations are increased in duration by the protein kinase C (PKC) inhibitor staurosporine and abolished by the PKC activating phorbol ester PMA. It is clear that CCK-8 and ACh do not activate receptor transduction mechanisms in an identical manner to generate oscillating [Ca2+]i signals.
Yule
D I
DI
MRC Secretory Control Research Group, University of Liverpool, UK.
Lawrie
A M
AM
Gallacher
D V
DV
D000109:Acetylcholine / Q000031:analogs & derivatives / Q000494:pharmacology*; D000470:Alkaloids; D000818:Animals; D002118:Calcium / Q000502:physiology*; D002468:Cell Physiological Phenomena; D002478:Cells, Cultured / Q000187:drug effects; D002766:Cholecystokinin / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D003600:Cytosol / Q000378:metabolism; D004848:Epithelium / Q000187:drug effects; D008297:Male; D051379:Mice; D010179:Pancreas / Q000187:drug effects* / Q000502:physiology; D010507:Periodicity; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D015398:Signal Transduction / Q000187:drug effects* / Q000502:physiology; D012844:Sincalide / Q000031:analogs & derivatives / Q000494:pharmacology; D019311:Staurosporine; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D000470:Alkaloids; C058451:JMV 180; D002766:Cholecystokinin; D011493:Protein Kinase C; D019311:Staurosporine; D012844:Sincalide; D000109:Acetylcholine; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium