Increase of nitric oxide by L-arginine potentiates beta-endorphin- but not mu-, delta- or kappa-opioid agonist-induced antinociception in the mouse.
L-Arginine pretreated i.c.v. produced a time- and dose-dependent potentiation of beta-endorphin-induced inhibition of the tail-flick response in ICR mice. However, the inhibition of the tail-flick response induced by morphine, DAMGO ([D-Ala2,NMePhe4,Gly5-ol]enkephalin), DPDPE ([D-Pen2,D-Pen5]enkephalin or U50,488H given i.c.v. was not potentiated by i.c.v. pretreated L-arginine. The results indicate that L-arginine selectively potentiates antinociception induced by epsilon-opioid receptor agonist, but not mu-, delta- or kappa-opioid receptor agonist. L-Arginine pretreated i.t. did not potentiate i.c.v. administered beta-endorphin-induced inhibition of the tail-flick response, indicating that the potentiating effect of L-arginine on beta-endorphin-induced antinociception is located at the supraspinal sites but not at the spinal sites.
Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee 53226.
J Y
JY
Xu
L F
LF
Tseng
D000700:Analgesics / Q000494:pharmacology*; D000818:Animals; D001120:Arginine / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D007276:Injections, Intraventricular; D007278:Injections, Spinal; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D009294:Narcotics / Q000494:pharmacology*; D009569:Nitric Oxide / Q000378:metabolism*; D010147:Pain Measurement / Q000187:drug effects; D011930:Reaction Time / Q000187:drug effects; D017465:Receptors, Opioid, delta / Q000187:drug effects; D017473:Receptors, Opioid, kappa / Q000187:drug effects; D017450:Receptors, Opioid, mu / Q000187:drug effects; D001615:beta-Endorphin / Q000494:pharmacology*
D000700:Analgesics; D009294:Narcotics; D017465:Receptors, Opioid, delta; D017473:Receptors, Opioid, kappa; D017450:Receptors, Opioid, mu; D009569:Nitric Oxide; D001615:beta-Endorphin; D001120:Arginine