Ryanodine induced block of a cloned human cardiac potassium channel.
The effects of ryanodine in a cloned human cardiac potassium channel (hKvl.5) expressed in a stable mouse L cell line was studied using whole cell voltage clamp technique. Ryanodine in a dose dependent manner (10(-7) - 10(-5) M) reduced the peak current as well as the current at the end of a 250 ms pulse. Dose response data fitted to a Hill equation yielded IC50 of 1.2 microM. The degree of block was not voltage dependent. Peak current was reduced from 43.6 +/- 12.5% at 10(-5) M to 11.3 +/- 4.8% at 10(-7) M ryanodine. Ryanodine reduced the tail current amplitude without changing the time course relative to the control. The inhibition was only partially reversible at concentrations below 10(-6) M.
Department of Physiology, Meharry Medical College, Nashville, Tennessee, USA.
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D000818:Animals; D002460:Cell Line; D006801:Humans; D051379:Mice; D009206:Myocardium / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D026902:Potassium Channel Blockers; D015221:Potassium Channels / Q000235:genetics; D011994:Recombinant Proteins / Q000037:antagonists & inhibitors / Q000235:genetics; D012433:Ryanodine / Q000494:pharmacology*; D014162:Transfection
D026902:Potassium Channel Blockers; D015221:Potassium Channels; D011994:Recombinant Proteins; D012433:Ryanodine