Intrathecally administered N-methyl-D-aspartate increases persistent hindlimb flexion in rat.
Persistent hindlimb flexion was induced in pentobarbital anesthetized rats using a prolonged, electrical stimulus. Intrathecal (i.t.) N-methyl-D-aspartate NMDA) (1 mM, 5 microliters) applied prior to stimulation increased flexion relative to stimulated controls subsequent to stimulation (156%); 3 days later (109%) and after spinalization at 3 days (91%). Pretreatment with MK-801 (3 mg/kg, i.p.) prevented the enhancement of flexion. Withdrawal latencies to a thermal stimulus also were measured. I.t. NMDA plus stimulation reduced mean latency relative to controls only subsequent to stimulation. Latencies were increased by MK-801 post-injection, post-stimulation and at 3 days. The results suggest that the induction of persistent hindlimb flexion depends upon spinal NMDA receptors.
Moore
R D
RD
Department of Physiology, University of New England, College of Osteopathic Medicine, Biddeford, ME 04005.
Mokler
D J
DJ
Winterson
B J
BJ
D000818:Animals; D003655:Decerebrate State / Q000503:physiopathology; D016291:Dizocilpine Maleate / Q000494:pharmacology; D004558:Electric Stimulation; D005260:Female; D006614:Hindlimb / Q000187:drug effects*; D006358:Hot Temperature; D007278:Injections, Spinal; D008297:Male; D016202:N-Methylaspartate / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors
D016194:Receptors, N-Methyl-D-Aspartate; D016202:N-Methylaspartate; D016291:Dizocilpine Maleate