Heterogenous distribution of free calcium and propagation of calcium transient in gastric parietal cells revealed by digital imaging microscopyY Tsunoda, S Yodozawa and Y Tashiro Department of Physiology, Kansai Medical University, Osaka, Japan. Spatial and temporal changes of cytoplasmic free calcium concentration ([Ca2+]i) in single parietal cells of guinea pig were investigated with a digital imaging microscope equipped with a microspectrofluorometer, using a Ca2+-sensitive dye, fura-2. Intracellular distribution of [Ca2+]i was not homogeneous, but there were two kinds of [Ca2+]i gradient in the resting parietal cells, one a continuous gradient increasing towards the plasma membrane and a second discontinuous gradient (Ca2+ plateau) in some restricted regions of the cytoplasm. When treated with gastrin, only about 40% of parietal cells in the gastric gland responded with an almost twofold increase in the average resting [Ca2+]i of 52.4 +/- 7.1 nM. In the responding cells, the discontinuous plateaus transiently enlarged to the entire cytoplasm. In marked contrast, all of these cells responded to Ca2+ ionophore ionomycin. We also found that when provoked by gastrin Ca2+ transient in the parietal cells in the gastric gland often propagated to some adjacent cells, and occasionally spontaneous Ca2+ transient and oscillation were observed even in the resting state.
Volume 37,
Issue 7,
pp. 999-1005,
07/01/1989
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F. Noble, S. A. Wank, J. N. Crawley, J. Bradwejn, K. B. Seroogy, M. Hamon, and B. P. Roques International Union of Pharmacology. XXI. Structure, Distribution, and Functions of Cholecystokinin Receptors Pharmacol. Rev., December 1, 1999; 51(4): 745 - 781. [Abstract] [Full Text] [PDF] |
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