title: Influence of the membrane stabilizer diphenylhydantoin on potassium and sodium movements in skeletal muscle.
abstract: The membrane stabilizer diphenylhydantoin (DPH) did not alter the net content of Na, K, Ca or Mg in frog sartorius muscle freshly incubated or actively transporting Na and K following Na-loading and K-depletion. Resting influx of K from normal Ringer was significantly reduced by DPH, and this inhibition occurred in the ouabain-insensitive K-uptake. Inhibition of K-influx by DPH was overcome when [K]0 was raised to 10 mM, and Rb-influx was not sensitive to the inhibitor in 2.5 mM Rb-Ringer. Efflux of tracer K was reduced by DPH in the presence and absence of ouabain. Exchange of muscle Na was not affected under conditions in which K-exchange was significantly reduced, but DPH appeared to cause increased net loss of Na from muscles washed in Na-free medium. The inhibition of DPH of resting K-exchange was not sensitive to wide variations in [Na]0 or in [Ca]0. The results suggest that the effect of DPH on frog skeletal muscle in normal ionic environment is to reduce the resting, passive component of K-exchange across the fibre membrane. This effect is discussed in relation to the membrane stabilizing actions of diphenylhydantoin.
mesh_terms: D000818:Animals; D001001:Anura; D001693:Biological Transport, Active / Q000187:drug effects; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology; D008274:Magnesium / Q000378:metabolism / Q000494:pharmacology; D009132:Muscles / Q000187:drug effects / Q000378:metabolism*; D010042:Ouabain / Q000494:pharmacology; D010672:Phenytoin / Q000494:pharmacology*; D011188:Potassium / Q000378:metabolism* / Q000494:pharmacology; D011893:Rana esculenta; D012413:Rubidium / Q000378:metabolism; D012964:Sodium / Q000378:metabolism* / Q000494:pharmacology
chemical_list: D010042:Ouabain; D010672:Phenytoin; D012964:Sodium; D008274:Magnesium; D012413:Rubidium; D011188:Potassium; D002118:Calcium