title: Involvement of nitridergic and opioidergic pathways in the antinociception of gabapentin in the orofacial formalin test in mice.
abstract: BACKGROUND
  Pain is one of the most common problems in clinical medicine. There is considerable evidence that pharmacologic approaches are the most widely used therapeutic options to ameliorate persistent or chronic pain. In this study it was evaluated the effect of l-NAME and naltrexone in the antinociception induced by administration of gabapentin in the orofacial formalin test of mice.
  
  
  METHODS
  The algesiometer assay was performed by the administration of 20 μl of 2% formalin solution injected into the upper right lip of each mouse.
  
  
  RESULTS
  The dose of gabapentin that produces the 50% of the maximum possible effect (ED50) was significantly increased by the pretreatment with l-NAME or naltrexone.
  
  
  CONCLUSIONS
  These results suggest that gabapentin produce antinociception partly via the activation nitridergic pathways and opioid system.
authors.affiliation: Facultad de Medicina, Escuela de Química y Farmacia, Universidad Andrés Bello, Santiago, Chile; Facultad de Medicina, ICBM, Universidad de Chile, Santiago, Chile. Electronic address: hmiranda@med.uchile.cl.
authors.forename: Hugo F
authors.initials: HF
authors.lastname: Miranda
authors.affiliation: Dental School, Universidad Finis Terrae, Santiago, Chile.
authors.forename: Fernando
authors.initials: F
authors.lastname: Sierralta
authors.affiliation: Facultad de Medicina, ICBM, Universidad de Chile, Santiago, Chile.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Lux
authors.affiliation: Facultad de Odontología, Universidad de Chile, Santiago, Chile.
authors.forename: Rocío
authors.initials: R
authors.lastname: Troncoso
authors.affiliation: Facultad de Medicina, ICBM, Universidad de Chile, Santiago, Chile.
authors.forename: Natalia
authors.initials: N
authors.lastname: Ciudad
authors.affiliation: Facultad de Medicina, Escuela de Química y Farmacia, Universidad Andrés Bello, Santiago, Chile.
authors.forename: Ramiro
authors.initials: R
authors.lastname: Zepeda
authors.affiliation: Facultad de Medicina, ICBM, Universidad de Chile, Santiago, Chile.
authors.forename: Pilar
authors.initials: P
authors.lastname: Zanetta
authors.affiliation: Facultad de Medicina, Escuela de Química y Farmacia, Universidad Andrés Bello, Santiago, Chile; Hospital Clínico, Universidad de Chile, Santiago, Chile.
authors.forename: Viviana
authors.initials: V
authors.lastname: Noriega
authors.affiliation: Facultad de Medicina, ICBM, Universidad de Chile, Santiago, Chile; Hospital Clínico, Universidad de Chile, Santiago, Chile.
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Prieto
mesh_terms: D000588:Amines / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D000700:Analgesics / Q000494:pharmacology*; D000818:Animals; D003509:Cyclohexanecarboxylic Acids / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D000077206:Gabapentin; D008297:Male; D051379:Mice; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology*; D009271:Naltrexone / Q000494:pharmacology*; D009292:Narcotic Antagonists / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D010147:Pain Measurement / Q000187:drug effects*; D015398:Signal Transduction / Q000187:drug effects*; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology*
chemical_list: D000588:Amines; D000700:Analgesics; D003509:Cyclohexanecarboxylic Acids; D009292:Narcotic Antagonists; D005680:gamma-Aminobutyric Acid; D009271:Naltrexone; D000077206:Gabapentin; D019001:Nitric Oxide Synthase; D019331:NG-Nitroarginine Methyl Ester
keywords: Gabapentin; Naltrexone; Orofacial formalin test; Tonic inflammatory pain; l-NAME