title: Possible involvement of nitric oxide in red nucleus stimulation-induced analgesia in the rat.
abstract: There is considerable evidence that nitric oxide (NO) plays a role in synaptic transmission in both central and peripheral nervous systems. Recent studies have suggested the involvement of the L-arginine-NO pathway in nociceptive transmission/modulation. Electrical stimulation of the red nucleus in the rat evokes potent analgesia. Microinjection of different concentrations of L-arginine (1 nmol-1 mumol), but not of D-arginine, produced quick and long-lasting analgesia. Pretreatment with N-nitro-L-arginine methyl ester (1 mumol), a nitric oxide synthase inhibitor, significantly prevented L-arginine-induced analgesia. Further, pretreatment of animals with methylene blue, a known guanylate cyclase inhibitor, also attenuated the development of analgesia. Our results suggest that L-arginine caused production of NO, which in turn activated the red nucleus analgesic system.
authors.affiliation: Division of Pharmacology, Central Drug Research Institute, Lucknow, India.
authors.forename: A
authors.initials: A
authors.lastname: Kumar
authors.forename: R
authors.initials: R
authors.lastname: Raghubir
authors.forename: B N
authors.initials: BN
authors.lastname: Dhawan
mesh_terms: D000698:Analgesia; D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000037:antagonists & inhibitors / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004558:Electric Stimulation; D008297:Male; D008751:Methylene Blue / Q000494:pharmacology; D019331:NG-Nitroarginine Methyl Ester; D009569:Nitric Oxide / Q000502:physiology*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D051381:Rats; D012012:Red Nucleus / Q000187:drug effects* / Q000502:physiology
chemical_list: D009569:Nitric Oxide; D001120:Arginine; D019001:Nitric Oxide Synthase; D008751:Methylene Blue; D019331:NG-Nitroarginine Methyl Ester