INDUCTION OF MUSCLE-RELAXING FACTOR BY STAPHYLOCOCCAL ALPHA-TOXIN

Brain tissue and serum from mice intracerebrally injected with 1 mu g of staphylococcal alpha-toxin contained elevated amounts of a naturall y occurring brain tissue component(s) called muscle-relaxing factor (M RF). MRF induced reversible, generalized, flaccid paralysis of mice af ter intracerebral but not intraperitoneal or intravenous administratio n. MRF (i) was soluble in Hanks balanced salt solution and in acidifie d (pH 2) Hanks balanced salt solution, in which it partitions into eth yl acetate, acetone, and methanol; (ii) was separated from some pigmen ts by thin-layer chromatography on silica gel plates; (iii) did not co migrate with prostaglandin and leukotriene standards during high-press ure liquid chromatography with a mu Bondapak fatty acid column; and (i v) did not contain amino acids, exhibit absorption maxima at a wavelen gth range of 210 to 600 nm, or fluoresce when exposed to W light. MRF has been detected in rabbit brain that has been stored frozen at - 70 degrees C and has been enhanced in vitro in slices of both mouse and r abbit brain following incubation of the brain slices with staphylococc al alpha-toxin. Studies to identify the chemical nature of MRF and the mechanism by which, in mice, it induces reversible, flaccid paralysis of voluntary muscle are continuing.