SECOND MESSENGERS AND THE REGULATION OF CA 2+ FLUXES BY CA 2+ ‐MOBILIZING AGONISTS IN RAT LIVER

摘要: Summary Knowledge of the mechanism action Ca2+-mobilizing agonists in liver has progressed considerably following discovery that their interaction with specific receptors on plasma membrane is accompanied by hydrolysis PIP2 and generation second messengers diacylglycerol IP3, for activation protein kinase C mobilization intracellular Ca2+, respectively. Although messenger functions IP3 these actions seem well established, it not yet clear how are able to regulate Ca2+ influx across membrane, an event which crucial those dependent maintenance elevated level cytosolic Whilst there evidence existence more than one pathway liver, appears each instance process regulated differently through volage-sensitive channels known occur excitable tissues. At present whether any pathways direct coupling agonist receptor outer surface or regulation involves production some messenger(s). However, indirect from a number tissues favour involvement both IP4 influx. The may remains be but been proposed entry into cell occurs connecting endoplasmic reticulum, release lumen reticulum. Although glucagon (or cyclic AMP) activates same as agonists, marked potentiation AMP induced provided powerful system study liver. Whether this ion exchange (such Ca2+/Na+ exchange) determined. Results suggests inhibited neomycin, acidic pH, depolarization membrane. observation synergistically potentiates correlate reported ability induce accumulation vasopressin, all consistent notion involved regulating little about transport itself, studies coupled recent finding can different pathways, set lead better understanding important near future.