Mechanisms of spinal reflex depressant effects of CS-722, a newly synthesized centrally acting muscle relaxant, in spinal rats.
The mechanisms of the depressant action of (R)-4-chloro-2-(2-hydroxy-3-morpholinopropyl)-5-phenyl-4-isoxaz olin-3-one hydrochloride (CS-722), a newly synthesized centrally acting muscle relaxant, on spinal reflexes were investigated in spinal rats. The drug CS-722 (50 mg/kg, i.v.) depressed the polysynaptic reflex but was less effective on the monosynaptic reflex. Eperisone-HCl (10 mg/kg, i.v.) and baclofen (2 mg/kg, i.v.) markedly decreased the monosynaptic and polysynaptic reflexes, with longer durations than CS-722; CS-722, eperisone and baclofen depressed the dorsal root reflex. The excitability of the motoneurone was reduced by CS-722 and eperisone. Excitability of the primary afferent fibres was reduced by CS-722, while eperisone and baclofen had no effect. Both CS-722 and eperisone did not have a depressant influence on the focal synaptic potential. These results suggest that CS-722 and eperisone but not baclofen, have a common motoneurone-membrane-stabilizing action and that this action may contribute, in part, to the spinal reflex depressant effects of CS-722 and eperisone.
Tanabe
M
M
New Lead Research Laboratories, Sankyo Co. Ltd, Tokyo, Japan.
Kaneko
T
T
Tonohiro
T
T
Iwata
N
N
D000818:Animals; D003655:Decerebrate State / Q000503:physiopathology; D003864:Depression, Chemical; D004558:Electric Stimulation; D005071:Evoked Potentials / Q000187:drug effects; D007555:Isoxazoles / Q000494:pharmacology*; D008297:Male; D009025:Morpholines / Q000494:pharmacology*; D009125:Muscle Relaxants, Central / Q000494:pharmacology*; D009475:Neurons, Afferent / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D012018:Reflex / Q000187:drug effects*; D012023:Reflex, Monosynaptic / Q000187:drug effects; D013116:Spinal Cord / Q000187:drug effects*
D007555:Isoxazoles; D009025:Morpholines; D009125:Muscle Relaxants, Central; C077576:CS 722