title: Roles of the rostroventromedial medulla and the spinal 5-HT(1A) receptor in descending antinociception induced by motor cortex stimulation in the neuropathic rat.
abstract: Electric stimulation of the primary motor cortex (M1) has been effective in suppressing pain-related responses in neuropathic as well as healthy control animals. We studied whether the rostroventromedial medulla (RVM) or the spinal 5-HT(1A) receptor contributes to antinociception induced by stimulation of M1 in neuropathic animals. Assessments of the noxious heat-evoked limb withdrawal reflecting spinal nociception was performed in rats with spinal nerve ligation-induced peripheral neuropathy under light pentobarbital anesthesia. Spinal antinociception induced by electric stimulation of M1 was reduced following block of the RVM with intramedullary injection of muscimol, a GABA(A) receptor agonist, or following intrathecal administration of WAY-100635, a 5-HT(1A) receptor antagonist. The results indicate that the RVM and the descending serotonergic pathway acting on the spinal 5-HT(1A) receptor contribute to spinal antinociception induced by M1 stimulation in neuropathic animals.
authors.affiliation: Biomedicum Helsinki, Institute of Biomedicine/Physiology, POB 63, University of Helsinki, FIN-00014 Helsinki, Finland.
authors.forename: Hanna
authors.initials: H
authors.lastname: Viisanen
authors.forename: Antti
authors.initials: A
authors.lastname: Pertovaara
mesh_terms: D000818:Animals; D004599:Electric Stimulation Therapy; D058785:GABA-A Receptor Agonists; D008297:Male; D008526:Medulla Oblongata / Q000503:physiopathology*; D009044:Motor Cortex / Q000503:physiopathology*; D009118:Muscimol / Q000494:pharmacology; D010146:Pain / Q000378:metabolism / Q000503:physiopathology*; D059408:Pain Management; D010523:Peripheral Nervous System Diseases / Q000378:metabolism / Q000503:physiopathology* / Q000628:therapy; D010879:Piperazines / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D051381:Rats; D044282:Receptor, Serotonin, 5-HT1A / Q000502:physiology*; D058829:Serotonin 5-HT1 Receptor Antagonists; D013116:Spinal Cord / Q000378:metabolism* / Q000503:physiopathology
chemical_list: D058785:GABA-A Receptor Agonists; D010879:Piperazines; D011725:Pyridines; D058829:Serotonin 5-HT1 Receptor Antagonists; D044282:Receptor, Serotonin, 5-HT1A; D009118:Muscimol; C090413:N-(2-(4-(2-methoxyphenyl)-1-piperazinyl)ethyl)-N-(2-pyridinyl)cyclohexanecarboxamide