title: Analgesic effects of dexmedetomidine in vincristine-evoked painful neuropathic rats.
abstract: Dexmedetomidine, which is a selective α2-adrenoceptor agonist, was recently introduced into clinical practice for its analgesic properties. The purpose of this study was to evaluate the effects of dexmedetomidine in a vincristine-evoked neuropathic rat models. Sprague-Dawley rats were injected intraperitoneally with vincristine or saline (0.1 mg/kg/day) using a 5-day-on, 2-day-off schedule for 2 weeks. Saline and dexmedetomidine (12.5, 25, 50, and 100 µg/kg) were injected to rats developed allodynia 14 days after vincristine injection, respectively. We evaluated allodynia at before, 15, 30, 60, 90, 120, 180, and 240 min, and 24 hr after intraperitoneal drug (normal saline or dexmedetomidine) injection. Saline treatment did not show any differences for all the allodynia. Maximal paw withdrawal thresholds to mechanical stimuli were 3.0 ± 0.4, 9.1 ± 1.9, 13.0 ± 3.6, 16.6 ± 2.4, and 24.4 ± 1.6 g at saline, 12.5, 25, 50, and 100 µg/kg dexmedetomidine injection, respectively. Minimal withdrawal frequency to cold stimuli were 73.3 ± 4.2, 57.1 ± 6.8, 34.3 ± 5.7, 20.0 ± 6.2, and 14.3 ± 9.5 g at saline, 12.5, 25, 50, and 100 µg/kg dexmedetomidine injection, respectively. Dexmedetomidine shows a dose-dependent antiallodynic effect on mechanical and cold stimuli in vincristine-evoked neuropathic rat models (P < 0.05).
authors.affiliation: Department of Anesthesiology and Pain Medicine, Seoul St. Mary's Hospital, The Catholic University of Korea College of Medicine, Seoul, Korea.
authors.forename: Hue Jung
authors.initials: HJ
authors.lastname: Park
authors.forename: Young Hoon
authors.initials: YH
authors.lastname: Kim
authors.forename: Hyun Jung
authors.initials: HJ
authors.lastname: Koh
authors.forename: Chul-Soo
authors.initials: CS
authors.lastname: Park
authors.forename: Seung-hee
authors.initials: SH
authors.lastname: Kang
authors.forename: Jong-Ho
authors.initials: JH
authors.lastname: Choi
authors.forename: Dong Eon
authors.initials: DE
authors.lastname: Moon
mesh_terms: D000700:Analgesics / Q000627:therapeutic use*; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D020927:Dexmedetomidine / Q000627:therapeutic use*; D004195:Disease Models, Animal; D006930:Hyperalgesia / Q000139:chemically induced / Q000188:drug therapy*; D007274:Injections, Intraperitoneal; D008297:Male; D017288:Pain Threshold; D051381:Rats; D017207:Rats, Sprague-Dawley; D014750:Vincristine / Q000633:toxicity
chemical_list: D000700:Analgesics; D014750:Vincristine; D020927:Dexmedetomidine