N-methyl-D-aspartate (NMDA)-mediated muscle relaxant action of flupirtine in rats.
The present study examined in urethane-chloralose anaesthetized rats whether N-methyl-D-aspartate (NMDA) is involved in the depressant effect of flupirtine on the monosynaptic Hoffmann (H)-reflex recorded from plantar foot muscles and on polysynaptic flexor reflexes recorded from tibialis muscle. Intrathecal administration of both the specific NMDA antagonist (-)-2-amino-7-phosphonoheptanoate and of flupirtine depressed the polysynaptic flexor reflex without affecting the monosynaptic H-reflex. In contrast, the non-NMDA antagonist 6,7-dinitroquinoxaline-2,3-dione depressed the H-reflex without affecting the flexor reflex. The depressant effect of flupirtine on the flexor reflex was prevented by co-administration of NMDA, but not by co-administration of the non-NMDA agonist alpha-amino-3-hydroxy-5-tertbutyl-4-isoxazolepropionic acid. These observations suggest that NMDA might be involved in the action of flupirtine.
Department of Neurology, RWTH Aachen, Germany.
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M
Schwarz
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F
Block
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Pergande
D000631:Aminopyridines / Q000494:pharmacology*; D000700:Analgesics / Q000494:pharmacology*; D000818:Animals; D004305:Dose-Response Relationship, Drug; D006181:H-Reflex / Q000187:drug effects; D007274:Injections, Intraperitoneal; D007278:Injections, Spinal; D008297:Male; D009125:Muscle Relaxants, Central / Q000494:pharmacology*; D016202:N-Methylaspartate / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D016194:Receptors, N-Methyl-D-Aspartate / Q000819:agonists / Q000037:antagonists & inhibitors; D012018:Reflex / Q000187:drug effects
D000631:Aminopyridines; D000700:Analgesics; D009125:Muscle Relaxants, Central; D016194:Receptors, N-Methyl-D-Aspartate; D016202:N-Methylaspartate; C034161:flupirtine