Effect of a centrally-acting muscle relaxant, eperisone hydrochloride, on muscle sympathetic nerve activity in humans.

The sympatho-modulating effects of eperisone hydrochloride, a centrally acting muscle relaxant, on microneurographically recorded muscle sympathetic nerve activity (MSA) were analyzed in human volunteers. A single dose of 300 mg of eperisone was orally administered to 19 healthy subjects aged between 19 and 27, and effects on 1) spontaneous MSA in 30 degrees head-up tilted position, 2) resting MSA and responsiveness to standing, 3) exercise-induced enhancement of MSA were observed. Eperisone has a sympatho-suppressive action in resting skeletal muscles, but has no effect on MSA in actively contracting muscles, e.g. standing, hand-gripping. The sympatho-suppressive effect of eperisone may be related to the drug-induced increase of blood low in the resting skeletal muscles; also it may be one more mechanism through which the drug can exert its muscle relaxant action.