title: Dipyrone into the nucleus raphe magnus inhibits the rat nociceptive tail-flick reflex.
abstract: Recent studies suggest that non-steroidal anti-inflammatory drugs have central sites of action which contribute to their analgesic efficacy. In the present study microinjections of the non-steroidal anti-inflammatory drug, dipyrone, were made into the medullary nucleus raphe magnus of lightly pentobarbital-anesthetized rats; 25, 50, 100 and 200 micrograms of dipyrone dose-dependently inhibited the nociceptive tail-flick withdrawal reflex. These results suggest that dipyrone modulates bulbospinal neurons in the nucleus raphe magnus to inhibit spinal nociceptive reflexes; thus, new routes of administration and methods of application may be possible for these analgesic agents.
authors.affiliation: Department of Pharmacology, College of Medicine, University of Oklahoma, Oklahoma City 73190, USA.
authors.forename: S L
authors.initials: SL
authors.lastname: Jones
mesh_terms: D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage / Q000494:pharmacology*; D004177:Dipyrone / Q000008:administration & dosage / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D008297:Male; D008845:Microinjections; D010147:Pain Measurement; D011903:Raphe Nuclei; D051381:Rats; D017207:Rats, Sprague-Dawley; D012018:Reflex / Q000187:drug effects*
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D004177:Dipyrone