Signaling of Ca2+ release and contraction in cardiac myocytes.
Cross signaling between Ca2+ channel and ryanodine receptor was explored in whole cell clamped rat ventricular myocyte under conditions where global myoplasmic Ca2+ concentrations were strongly buffered by dialyzing the myocytes with high concentrations of Fura 2 and EGTA. Ca2+ channel and ryanodine receptor were respectively activated by a depolarizing pulse to -10 mV and rapid (< 50 ms) application of 5 mM caffeine. Temporal analysis of kinetics of inactivation of Ca2+ channel with respect to the time of application of caffeine pulse provided experimental evidence that signalling between the ryanodine and Ca2+ channel is mediated exclusively through the Ca2+ microdomains surrounding the DHP/ryanodine receptor complex independent of global myoplasmic Ca2+ concentrations.
Georgetown University School of Medicine, Washington, DC 20007, USA.
M
M
Morad
D000818:Animals; D002118:Calcium / Q000502:physiology*; D015220:Calcium Channels / Q000502:physiology*; D002478:Cells, Cultured; D009124:Muscle Proteins / Q000502:physiology*; D009200:Myocardial Contraction / Q000502:physiology*; D051381:Rats; D019837:Ryanodine Receptor Calcium Release Channel; D015398:Signal Transduction; D016276:Ventricular Function
D015220:Calcium Channels; D009124:Muscle Proteins; D019837:Ryanodine Receptor Calcium Release Channel; D002118:Calcium