Abstract: Research Article1 August 1993free access Agonist-induced localized Ca2+ spikes directly triggering exocytotic secretion in exocrine pancreas. Y. Maruyama Y. Maruyama Department of Physiology, Jichi Medical School, Tochigi, Japan. Search for more papers by this author G. Inooka G. Inooka Department of Physiology, Jichi Medical School, Tochigi, Japan. Search for more papers by this author Y.X. Li Y.X. Li Department of Physiology, Jichi Medical School, Tochigi, Japan. Search for more papers by this author Y. Miyashita Y. Miyashita Department of Physiology, Jichi Medical School, Tochigi, Japan. Search for more papers by this author H. Kasai H. Kasai Department of Physiology, Jichi Medical School, Tochigi, Japan. Search for more papers by this author Y. Maruyama Y. Maruyama Department of Physiology, Jichi Medical School, Tochigi, Japan. Search for more papers by this author G. Inooka G. Inooka Department of Physiology, Jichi Medical School, Tochigi, Japan. Search for more papers by this author Y.X. Li Y.X. Li Department of Physiology, Jichi Medical School, Tochigi, Japan. Search for more papers by this author Y. Miyashita Y. Miyashita Department of Physiology, Jichi Medical School, Tochigi, Japan. Search for more papers by this author H. Kasai H. Kasai Department of Physiology, Jichi Medical School, Tochigi, Japan. Search for more papers by this author Author Information Y. Maruyama1, G. Inooka1, Y.X. Li1, Y. Miyashita1 and H. Kasai1 1Department of Physiology, Jichi Medical School, Tochigi, Japan. The EMBO Journal (1993)12:3017-3022https://doi.org/10.1002/j.1460-2075.1993.tb05970.x PDFDownload PDF of article text and main figures. ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinked InMendeleyWechatReddit Figures & Info We investigated how agonist-induced patterned rises in cytosolic Ca2+ concentration ([Ca2+]i) regulate exocytotic secretion in the rat pancreatic acinar cell. The distribution of [Ca2+]i was visualized with a confocal microscope, which revealed that a Ca2+ ionophore, A23187, induced slow and homogeneous [Ca2+]i rises, while acetylcholine (ACh) always triggered primary Ca2+ spikes at the granular area which bears secretory granules. Secretion was monitored by measuring capacitance with the patch clamp method. Errors in the estimates of membrane capacitance (C) due to changes in conductance (G) were experimentally as well as theoretically evaluated to be one-tenth of the actual signals. We found that A23187 raised G without changing C at a low concentration, while it triggered asynchronous rises in G and C with lags in C, at a high concentration. By contrast, ACh triggered simultaneous rapid rises in G and C. Our results support the hypothesis that exocytotic secretion is less sensitive to Ca2+ than to ion channels and is directly caused by agonist-induced primary Ca2+ spikes at the granular area. It is therefore suggested that spatio-temporal patterns of Ca2+ oscillations could play a key role in exocytotic secretion from the exocrine acinar cell. Previous ArticleNext Article Volume 12Issue 81 August 1993In this issue RelatedDetailsLoading ...