title: Co-administration of MK-801 and morphine attenuates neuropathic pain in rat.
abstract: Partial peripheral nerve injury often leads to chronic pain states, including allodynia and hyperalgesia. The purpose of this study was to investigate the involvement of the N-methyl-D-aspartate and opioid receptors in the behavioural responses following chronic constriction nerve injury (CCI). The animals were injected a combination of MK-801 (0.3 mg/kg, 20 min before, and 6 h after the operation) and morphine (8 mg/kg, 30 min prior to the operation) and were tested for allodynia and hyperalgesia reactions at 0, 3, 7, 14, 21 and 28 days after CCI. Compound action potentials were also recorded from the injured nerve 2 weeks post-operation to indicate nerve injury state electrophysiologically. Our results indicate that the CCI model importantly influences the behavioural responses to both the thermal and mechanical stimulations. Also, the pre-emptive co-administration of MK-801 and morphine has suppressive effects on the cold allodynia but a slight alleviation on the mechano-allodynia and heat hyperalgesia.
authors.affiliation: Department of Physiology, Neuroscience Research Center, School of Medicine, Shaheed Beheshti University of Medical Sciences, Tehran, I. R. Iran. hamiidi@yahoo.com
authors.forename: Gholam Ali
authors.initials: GA
authors.lastname: Hamidi
authors.forename: Homa
authors.initials: H
authors.lastname: Manaheji
authors.forename: Mahyar
authors.initials: M
authors.lastname: Janahmadi
authors.forename: Sayed Mohammad
authors.initials: SM
authors.lastname: Noorbakhsh
authors.forename: Mahmoud
authors.initials: M
authors.lastname: Salami
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000701:Analgesics, Opioid / Q000494:pharmacology*; D000818:Animals; D003080:Cold Temperature; D003251:Constriction, Pathologic / Q000150:complications; D016291:Dizocilpine Maleate / Q000494:pharmacology*; D004594:Electrophysiology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology*; D006930:Hyperalgesia / Q000188:drug therapy / Q000503:physiopathology; D008297:Male; D009020:Morphine / Q000494:pharmacology*; D010146:Pain / Q000188:drug therapy* / Q000209:etiology / Q000523:psychology; D010523:Peripheral Nervous System Diseases / Q000150:complications*; D010812:Physical Stimulation; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D000701:Analgesics, Opioid; D018691:Excitatory Amino Acid Antagonists; D016291:Dizocilpine Maleate; D009020:Morphine