title: Involvement of ventrolateral orbital cortex 5-HT 1-7 receptors in 5-HT induced depression of spared nerve injury allodynia.
abstract: The present study examined the roles of ventrolateral orbital cortex (VLO) 5-HT1, 5-HT2, 5-HT3, 5-HT4, 5-HT5, 5-HT6 and 5-HT7 receptor subtypes in mediating 5-HT-induced antiallodynic actions in the rat spared nerve injury (SNI) pain model. Changes in paw withdrawal threshold (PWT) were measured using von-Frey filaments. Microinjection of 5-HT (2, 5 and 10μg, in 0.5μl) into the VLO depressed allodynia induced by SNI, and the PWT increased in a dose-dependent manner. Microinjection of selective 5-HT1A, 5-HT2, 5-HT3, 5-HT4, 5-HT5A, 5-HT6 and 5-HT7 receptor antagonists, 1-(2-methoxyphenyl)-4-[4-(2-phthalimido)butyl] piperazine hydrobromide (NAN-190) (10μg), cyproheptadine (50ng), granisetron hydrochloride (granisetron) (10μg), 1-[2-[(methylsulfonyl)-amino]ethyl]-4-piperidinyl]methyl1-methyl-1H-indole-3-carboxylate (GR113808) (5μg), SB699551 dihydrochloride (SB699551) (10μg), SB258585 dihydrochloride (SB258585) (2μg) or SB269970 hydrochloride (SB269970) (10μg) into the VLO 5-min prior to 5-HT (10μg) injection, all antagonized the 5-HT-induced inhibition of allodynia. In addition, these antagonists applied alone to VLO did not influence allodynia. These results suggest that although 5-HT1-7 receptor subtypes in the VLO do not have a tonic modulatory action on the allodynia induced by SNI, they are involved in mediating the depression of the SNI allodynia produced by injection of 5HT into VLO.
authors.affiliation: Department of Physiology and Pathophysiology, Xi'an Jiaotong University College of Medicine, Yanta Road West 76#, Xi'an, Shaanxi 710061, PR China.
authors.forename: W J
authors.initials: WJ
authors.lastname: Xu
authors.forename: Y
authors.initials: Y
authors.lastname: Zhao
authors.forename: F Q
authors.initials: FQ
authors.lastname: Huo
authors.forename: J Q
authors.initials: JQ
authors.lastname: Du
authors.forename: J S
authors.initials: JS
authors.lastname: Tang
mesh_terms: D000818:Animals; D005625:Frontal Lobe / Q000187:drug effects* / Q000378:metabolism; D006930:Hyperalgesia / Q000378:metabolism*; D008297:Male; D009437:Neuralgia / Q000378:metabolism; D010147:Pain Measurement; D017288:Pain Threshold / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011985:Receptors, Serotonin / Q000378:metabolism*; D012701:Serotonin / Q000494:pharmacology*; D012702:Serotonin Antagonists / Q000494:pharmacology*
chemical_list: D011985:Receptors, Serotonin; D012702:Serotonin Antagonists; D012701:Serotonin