title: Riboflavin reduces hyperalgesia and inflammation but not tactile allodynia in the rat.
abstract: Vitamin B2 (riboflavin) has been proposed as a prophylactic therapy of migraine. However, so far there are no preclinical studies about the analgesic properties of this vitamin. The current study was designed to investigate the possible antinociceptive, antihyperalgesic and antiallodynic effect of riboflavin in formalin, carrageenan-induced thermal hyperalgesia, and spinal nerve ligation models, respectively. Oral riboflavin produced a dose-related antinociceptive (6.25-50 mg/kg), antihyperalgesic (25-150 mg/kg) and anti-inflammatory (50-150 mg/kg) effect. Gabapentin (100 mg/kg, positive control), but not riboflavin (150-600 mg/kg), reduced tactile allodynia in neuropathic rats. Riboflavin-induced antinociception in the formalin test was reversed by pretreatment with NG-L-nitro-arginine methyl ester and glibenclamide, but not by NG-D-nitro-arginine methyl ester or naloxone. Our results indicate that riboflavin is able to produce antinociception and anti-inflammatory, but not antiallodynic, effect in the rat. The effect of riboflavin could be due to the activation of K+ channels or nitric oxide release, but not activation of opioid mechanisms.
authors.affiliation: Departamento de Farmacobiología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Calzada Tenorios 235, Colonia Granjas Coapa, 14330 México, DF, Mexico. vgranados@prodigy.net.mx
authors.forename: Vinicio
authors.initials: V
authors.lastname: Granados-Soto
authors.forename: Flavio
authors.initials: F
authors.lastname: Terán-Rosales
authors.forename: Héctor I
authors.initials: HI
authors.lastname: Rocha-González
authors.forename: Gerardo
authors.initials: G
authors.lastname: Reyes-García
authors.forename: Roberto
authors.initials: R
authors.lastname: Medina-Santillán
authors.forename: Juan
authors.initials: J
authors.lastname: Rodríguez-Silverio
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Flores-Murrieta
mesh_terms: D000700:Analgesics / Q000494:pharmacology*; D000818:Animals; D002351:Carrageenan; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D005905:Glyburide / Q000494:pharmacology; D006930:Hyperalgesia / Q000188:drug therapy*; D007249:Inflammation / Q000139:chemically induced / Q000188:drug therapy*; D009043:Motor Activity / Q000187:drug effects; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009270:Naloxone / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology; D010147:Pain Measurement / Q000187:drug effects; D017288:Pain Threshold / Q000187:drug effects; D026902:Potassium Channel Blockers / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D012256:Riboflavin / Q000494:pharmacology*
chemical_list: D000700:Analgesics; D004791:Enzyme Inhibitors; D009292:Narcotic Antagonists; D026902:Potassium Channel Blockers; D009270:Naloxone; D002351:Carrageenan; D005905:Glyburide; D012256:Riboflavin; D019331:NG-Nitroarginine Methyl Ester