Sites of Action of a New Muscle Relaxant (Baclofen, Lioresal®, Ciba 34 647–Ba)

Abstract

Baclofen exerts a pronounced muscle-relaxant effect in non-anaesthetized animals. It reduces experimental rigidity in surgically and in anaemically decerebrated cats. It decreases monosynaptic and polysynaptic reflex transmission, as well as post-tetanic potentiation of the monosynaptic mass reflex in about the same dosage range. It reduces the activity of γ-moioneurones. It has no effect on neuromuscular transmission or on the sensory input from de-efferented muscle spindles and from slowly adapting pulmonary stretch receptors. The compound affords protection against convulsions induced by thiosemicarbazide and pentetrazole but not against those due to electric shock strychnine or picrotoxin.