To examine whether a decrease in cytosolic Ca2+ affects fibrillation p
otentials, we studied effects of dantolene on these potentials in dene
rvated rat muscle. Administered intraperitoneally, dantrolene sodium (
12-22 mg/kg) abolished fibrillation potentials and subthreshold oscill
ating potentials over 2.5-6 h without affecting excitability of the mu
scle to electrical stimulation. Fibrillation potentials reappeared 36-
96 h after administration of dantrolene. We suggest that cytosolic Ca2
+ has a specific role in generating fibrillations. (C) 1998 John Wiley
& Sons, Inc.