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Calcium oscillations in guinea‐pig pancreatic acinar cells exposed to carbachol, cholecystokinin and substance P.
Author(s) -
Sjödin L,
Dahlén H G,
Gylfe E
Publication year - 1991
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.1991.sp018905
Subject(s) - carbachol , medicine , endocrinology , agonist , cholecystokinin , chemistry , muscarinic agonist , substance p , stimulation , staurosporine , calcium , extracellular , protein kinase c , guinea pig , biology , receptor , neuropeptide , kinase , biochemistry
1. Cytoplasmic Ca2+ ([Ca2+]i) responses were studied in guinea‐pig pancreatic acinar cells during stimulation with cholecystokinin octapeptide (CCK‐8), substance P (SP) and carbachol. 2. Individual cells exhibited [Ca2+]i responses to all three agonists. 3. In the absence of external Ca2+, all the agonists initiated [Ca2+]i peaks which, particularly at high agonist concentrations, rapidly declined. 4. SP induced repetitive monophasic [Ca2+]i transients which started from basal [Ca2+]i even after elevation of the external Ca2+ concentration. 5. CCK‐8 triggered similar oscillations, which particularly at high agonist concentration or after elevating external Ca2+ became superimposed upon a sustained elevation of [Ca2+]i. 6. Carbachol‐induced oscillations were more complex with [Ca2+]i transients superimposed on slower waves. 7. At high carbachol concentrations or elevation of external Ca2+ the slow waves fused into a sustained increase of [Ca2+]i. 8. The protein kinase C (PKC) activator 12‐O‐tetradecanoylphorbol‐13‐acetate attenuated the agonist‐induced [Ca2+]i responses, and this effect was reversed by the PKC activator staurosporine. 9. The results indicate that oscillations of [Ca2+]i induced by SP, CCK‐8 and carbachol involve intracellular mobilization of Ca2+. 10. CCK‐8 and carbachol also cause a rise of [Ca2+]i by a mechanism more directly dependent on the presence of extracellular Ca2+. 11. In the case of carbachol the latter component is subject to oscillatory control. 12. The transition from oscillatory [Ca2+]i to sustained increase may be associated with inhibition of amylase release.