title: Effects of the calcium channel blockers Phα1β and ω-conotoxin MVIIA on capsaicin and acetic acid-induced visceral nociception in mice.
abstract: The effects of intrathecal administration of the toxins Phα1β and ω-conotoxin MVIIA were investigated in visceral nociception induced by an intraperitoneal injection of acetic acid and an intracolonic application of capsaicin. The pretreatments for 2h with the toxins reduced the number of writhes or nociceptive behaviors compared with the control mice. Phα1β administration resulted in an Imax of 84±6 and an ID50 of 12 (5-27), and ω-conotoxin MVIIA resulted in an Imax of 82±9 and an ID50 of 11 (4-35) in the contortions induced by the intraperitoneal injection of acetic acid. The administration of Phα1β resulted in an Imax of 64±4 and an ID50 of 18 (9-38), and ω-conotoxin MVIIA resulted in an Imax of 71±9 and an ID50 of 9 (1-83) in the contortions induced by intracolonic capsaicin administration. Phα1β (100/site) or ω-conotoxin MVIIA (30pmol/site) pretreatments caused a reduction in CSF glutamate release in mice intraperitoneally injected with acetic acid or treated with intracolonic capsaicin. The toxin pretreatments reduced the ROS levels induced by intraperitoneal acetic acid injection. Phα1β, but not ω-conotoxin MVIIA, reduced significantly the ROS levels induced by intracolonic capsaicin administration.
  
  
  CONCLUSIONS
  Phα1β is a ω-toxin with high therapeutic index and a broader action on calcium channels. It shows analgesic effect in several rodents' models of pain, including visceral pain, suggesting that this toxin has the potential to be used in clinical setting as a drug in the control of persistent pathological pain.
authors.affiliation: Programa de Pós Graduação Biomedicina e Medicina, Instituto de Ensino e Pesquisa da Santa Casa, Belo Horizonte, MG, Brazil.
authors.forename: Danuza Montijo
authors.initials: DM
authors.lastname: Diniz
authors.affiliation: Programa de Pós-Graduação em Genética e Toxicologia Aplicada (PPGGTA), Universidade Luterana do Brasil (ULBRA), Canoas, RS, Brazil.
authors.forename: Alessandra Hubner
authors.initials: AH
authors.lastname: de Souza
authors.affiliation: Programa de Pós Graduação em Farmacologia Bioquimica e Molecular, Faculdade Medicina UFMG, Belo Horizonte, MG, Brazil.
authors.forename: Elizete Maria Rita
authors.initials: EM
authors.lastname: Pereira
authors.affiliation: Programa de Pós Graduação Biomedicina e Medicina, Instituto de Ensino e Pesquisa da Santa Casa, Belo Horizonte, MG, Brazil.
authors.forename: Juliana Figueira
authors.initials: JF
authors.lastname: da Silva
authors.affiliation: Programa de Pós Graduação Biomedicina e Medicina, Instituto de Ensino e Pesquisa da Santa Casa, Belo Horizonte, MG, Brazil.
authors.forename: Flavia Karine
authors.initials: FK
authors.lastname: Rigo
authors.affiliation: Programa de Pós Graduação em Farmacologia Bioquimica e Molecular, Faculdade Medicina UFMG, Belo Horizonte, MG, Brazil.
authors.forename: Marco Aurélio
authors.initials: MA
authors.lastname: Romano-Silva
authors.affiliation: Programa de Pós Graduação Biomedicina e Medicina, Instituto de Ensino e Pesquisa da Santa Casa, Belo Horizonte, MG, Brazil.
authors.forename: Nancy
authors.initials: N
authors.lastname: Binda
authors.affiliation: Programa de Pós Graduação Biomedicina e Medicina, Instituto de Ensino e Pesquisa da Santa Casa, Belo Horizonte, MG, Brazil.
authors.forename: Célio J
authors.initials: CJ
authors.lastname: Castro
authors.affiliation: Fundação Ezequiel Dias (FUNED), Belo Horizonte, MG, Brazil.
authors.forename: Marta Nascimento
authors.initials: MN
authors.lastname: Cordeiro
authors.affiliation: Programa de Pós Graduação em Farmacologia UFSM, Santa Maria, RS, Brazil.
authors.forename: Juliano
authors.initials: J
authors.lastname: Ferreira
authors.affiliation: Programa de Pós Graduação Biomedicina e Medicina, Instituto de Ensino e Pesquisa da Santa Casa, Belo Horizonte, MG, Brazil; Programa de Pós Graduação em Farmacologia Bioquimica e Molecular, Faculdade Medicina UFMG, Belo Horizonte, MG, Brazil. Electronic address: marcusvgomez@gmail.com.
authors.forename: Marcus Vinicius
authors.initials: MV
authors.lastname: Gomez
mesh_terms: D019342:Acetic Acid / Q000008:administration & dosage / Q000494:pharmacology; D000285:Administration, Rectal; D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D002211:Capsaicin / Q000008:administration & dosage / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D018698:Glutamic Acid / Q000134:cerebrospinal fluid; D007278:Injections, Spinal; D008297:Male; D051379:Mice; D059225:Nociception / Q000187:drug effects*; D017382:Reactive Oxygen Species / Q000134:cerebrospinal fluid; D013111:Spider Venoms / Q000494:pharmacology*; D020960:omega-Conotoxins / Q000494:pharmacology*
chemical_list: D002121:Calcium Channel Blockers; C583821:Phalpha1beta toxin, Phoneutria nigriventer; D017382:Reactive Oxygen Species; D013111:Spider Venoms; D020960:omega-Conotoxins; D018698:Glutamic Acid; D019342:Acetic Acid; D002211:Capsaicin
keywords: Calcium channel blockers; Glutamate; ROS; Toxins; Visceral nociception