Biophysical Journal 48: 919-930 (1985)
© 1985 the Biophysical Society

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Lebrun, P Articles by Atwater, I Search for Related Content PubMed PubMed Citation Articles by Lebrun, P Articles by Atwater, I

Effects of the calcium channel agonist, BAY K 8644, on electrical activity in mouse pancreatic B-cells.

ABSTRACT

We studied the effects of the dihydropyridine derivative BAY K 8644 on the membrane potential of B-cells in mouse pancreatic islets. BAY K 8644, in a dose-dependent manner, decreased the spike frequency but increased the duration of the spikes elicited by glucose with or without quinine or tetraethylammonium (TEA). These effects were antagonized by cobalt and nifedipine but not by tetrodotoxin. The interval between spikes was proportionate to the duration of the spikes and the ratio of the interval to the spike duration was constant at all concentrations of BAY K 8644 tested. Peak inward current, estimated from the derivative of the action potential recorded in the presence of TEA, was increased by BAY K 8644 and decreased by nifedipine. BAY K 8644 elicited spike activity when the membrane was moderately depolarized by either 5.6 mM glucose or 15 mM K+, but did not change the membrane potential of the resting hyperpolarized B-cell. These results suggest that BAY K 8644 acts on the open Ca2+-channels. The threshold occurs at a membrane potential of -50 mV. Also, the modifications of the shape of the spikes appear to reflect specific changes in Ca2+ entry. We propose the existence of a Ca2+-induced Ca2+-channel inactivation process in the pancreatic B-cell.

This article has been cited by other articles:

				M. Zhang, P. Goforth, R. Bertram, A. Sherman, and L. Satin The Ca2+ Dynamics of Isolated Mouse {beta}-Cells and Islets: Implications for Mathematical Models Biophys. J., May 1, 2003; 84(5): 2852 - 2870. [Abstract] [Full Text] [PDF]

				R. Ouedraogo, Q.-A. Nguyen, M.-H. Antoine, C. Kane, M.J. Dunne, L. Pochet, B. Masereel, and P. Lebrun Insulinotropic Effect of New Glibenclamide Isosteres J. Pharmacol. Exp. Ther., May 1, 1999; 289(2): 625 - 631. [Abstract] [Full Text]

				H. Safayhi, H. Haase, U. Kramer, A. Bihlmayer, M. Roenfeldt, H. P.T. Ammon, M. Froschmayr, T. N. Cassidy, I. Morano, M. K. Ahlijanian, et al. L-Type Calcium Channels in Insulin-Secreting Cells: Biochemical Characterization and Phosphorylation in RINm5F Cells Mol. Endocrinol., May 1, 1997; 11(5): 619 - 629. [Abstract] [Full Text]