DIMETHYLSULFOXIDE (DMSO) BLOCKS CONDUCTION IN PERIPHERAL-NERVE C-FIBERS - A POSSIBLE MECHANISM OF ANALGESIA

Dimethylsulfoxide (DMSO) is readily absorbed through skin, and relieves musculoskeletal pain when applied topically to painful areas. We studied the effects of DMSO on C-type nerve fibers, which mediate pain sensation. DMSO was applied directly to exposed cat sural nerves. C fiber conduction velocity was slowed by DMSO, even in low concentrations (5-7% v/v). Higher concentration. completely blocked C fiber conduction, with a minimum blocking concentration of 9%. Onset of nerve block was almost immediate with 15% DMSO or higher concentrations. C fiber blockade may account for analgesia with DMSO.