Effects of eperisone-HCl on the stretch reflex in anesthetized cats

The effect of eperisone-HCl on the spinal stretch reflex was investigated in cats anesthetized with urethane-chloralose. The reflex activity, elicited by muscle stretches, was recorded from the split ventral root and analyzed using a cross-correlation histogram between the motoneuronal spikes and muscle stretches. Eperisone-HCl was intravenously applied at a dose of 5 mg/kg. It was found that eperisone weakly inhibited the reflex activity of tonic motoneurons (approximately 30%), and that of the phasic ones was either moderately (approximately 70%) or completely (100%) inhibited by eperisone. The cross-correlation analysis suggested that the membrane potentials of both tonic and phasic motoneurons are equally lowered by eperisone or that monosynaptic transmission from primary afferents of muscle spindles to motoneurons is inhibited by eperisone.