Regulation of gap junctional coupling in isolated pancreatic acinar cell pairs by cholecystokinin-octapeptide,vasoactive intestinal peptide (VIP) and a VIP-antagonist |
| |
Authors: | A. Ngezahayo H. -A. Kolb |
| |
Affiliation: | (1) University of Konstanz, Faculty of Biology, D-78464 Konstanz, Germany;(2) University of Tübingen, Institut of Physiology, I, Gmelinstr. 5, D-72076 Tübingen, Germany |
| |
Abstract: | Cholecystokinin-octapeptide (CCK-OP) induces a time- and dose-dependent decrease of gap Junctional conductance in isolated pairs of pancreatic acinar cells. In double whole-cell experiments, the time course could be described by the latency and the half-life time (t1/2) of cell-to-cell uncoupling. The latency shows a biphasic dependence on [CCK-OP] with a minimum of about 50 sec at 10–9m CCK-OP. In the presence of vasoactive intestinal peptide (VIP), the biphasic relationship is shifted to lower CCK-OP concentrations. The increase of latency at high concentrations of CCK-OP (> 1009m) was blocked by addition of a VIP-antagonist. t1/2 decreases monophasically with increasing [CCKOP]. Addition of GTPS to the pipette solution suppresses the [CCK-OP] dependence of the latency and potentiates the uncoupling phase. The kinetic data are discussed in terms of CCK binding to receptors of high and low affinity. Evidence is presented that secretion and cell-to-cell coupling are not related by an all-ornone process, but that for physiological CCK-OP concentrations, gap junctional uncoupling follows secretion.The authors would like to thank Dipl. Biol. F. Mendez for his support in software development for analysis of gap junctional conductance. The work was supported by the Graduiertenkolleg Biochemische Pharmakologie, the Herrmann und Lilly Schilling Stiftung and the Sonderforschungsbereich 156 of the Deutsche Forschungsgemeinschaft. |
| |
Keywords: | Gap junctions Double whole cell Cholecystokinin-octapeptide Vasoactive intestinal peptide (VIP) VIP antagonist Pancreatic acinar cells |
本文献已被 SpringerLink 等数据库收录! |
|