title: Role of neuronal nitric oxide synthase in the antiallodynic effects of intrathecal EGCG in a neuropathic pain rat model.
abstract: Epigallocatechin-3-gallate (EGCG), the major catechin in green tea, is known to have antioxidant activity against nitric oxide (NO) by scavenging free radicals, chelating metal ions, and inducing endogenous antioxidant enzymes. NO and NO synthase (NOS) play an important role in nociceptive processing. In this study, we examined the effects of intrathecal EGCG in neuropathic pain induced by spinal nerve ligation and the possible involvement of NO. Intrathecal EGCG attenuated mechanical allodynia in spinal nerve ligated-rats, compared to sham-operated rats, with a maximal possible effect of 69.2%. This antinociceptive effect was reversed by intrathecal pretreatment with l-arginine, a precursor of NO. Intrathecal EGCG also blocked the increase in nNOS expression in the spinal cord of spinal nerve-ligated rats, but iNOS expression was not significantly suppressed. These findings suggest that intrathecal EGCG could produce an antiallodynic effect against spinal nerve ligation-induced neuropathic pain, mediated by blockade of nNOS protein expression and inhibition of the pronociceptive effects of NO.
authors.affiliation: Department of Anesthesiology and Pain Medicine, Chonnam National University, Medical School, Gwangju, Republic of Korea.
authors.forename: Jeong Il
authors.initials: JI
authors.lastname: Choi
authors.forename: Woong Mo
authors.initials: WM
authors.lastname: Kim
authors.forename: Hyung Gon
authors.initials: HG
authors.lastname: Lee
authors.forename: Yeo Ok
authors.initials: YO
authors.lastname: Kim
authors.forename: Myung Ha
authors.initials: MH
authors.lastname: Yoon
mesh_terms: D000818:Animals; D001120:Arginine / Q000378:metabolism / Q000494:pharmacology; D002392:Catechin / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors / Q000494:pharmacology / Q000627:therapeutic use; D004195:Disease Models, Animal; D005121:Extremities / Q000503:physiopathology; D006930:Hyperalgesia / Q000188:drug therapy* / Q000503:physiopathology; D007278:Injections, Spinal; D008026:Ligation; D008297:Male; D009437:Neuralgia / Q000188:drug therapy* / Q000503:physiopathology; D009569:Nitric Oxide / Q000378:metabolism; D052248:Nitric Oxide Synthase Type I / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013116:Spinal Cord / Q000201:enzymology / Q000378:metabolism; D013127:Spinal Nerves
chemical_list: D009569:Nitric Oxide; D002392:Catechin; D001120:Arginine; C045651:epigallocatechin gallate; D052248:Nitric Oxide Synthase Type I