Cardiac ATP-sensitive K+ channels. Evidence for preferential regulation by glycolysis.

摘要: The ability of glycolysis, oxidative phosphorylation, the creatine kinase system, and exogenous ATP to suppress ATP-sensitive K+ channels prevent cell shortening were compared in patch-clamped single guinea pig ventricular myocytes. In cell-attached patches on myocytes permeabilized at one end with saponin, activated by removing from bath, could be closed equally well or substrates for endogenous production glycolysis (with mitochondrial inhibitor FCCP present), system. presence an ATP-consuming however, glycolytic present) superior either phosphorylation system suppressing channels. All three groups effective preventing shortening. 6 38 excised inside-out membrane patches, bath suppressed a complete set ATP-producing steps but not individual substrates, which is consistent key enzymes located near these patches. Under whole-cell voltage-clamp conditions, inclusion 15 mM patch electrode solution dialyzing interior did activation current under control conditions during exposure metabolic inhibition. isolated arterially perfused rabbit interventricular septa, selective inhibition caused immediate increase 42K+ efflux rate, was prevented 100 microM glyburide, known blocker These observations suggest that are associated cardiac. intracellular competition high (e.g., beating heart) act as preferential source