title: Consequence of hyperhomocysteinaemia on α1-adrenoceptor-mediated contraction in the rat corpus cavernosum: the role of reactive oxygen species.
abstract: OBJECTIVE
  Our main objective was to investigate the mechanisms underlying the effects of hyperhomocysteinaemia (HHcy) on contractile response mediated by α1-adrenoceptors in the rat corpus cavernosum.
  
  
  METHODS
  Concentration-response curves for phenylephrine (PE) were obtained in strips of corpus cavernosum, in absence or after incubation with tiron, tempol or polyethylene glycol (PEG)-catalase combined or not with tempol. We also measured the superoxide anion (O2(-)) and hydrogen peroxide (H2O2) generation, superoxide dismutase (SOD) and catalase activity and α-actin expression in rat corpus cavernosum from both groups.
  
  
  RESULTS
  HHcy increased PE-induced contraction in cavernosal strips. Tiron, PEG-catalase or tempol increased PE-induced contraction in strips from control rats, but it was not altered by tiron or PEG-catalase in HHcy rats, whereas tempol reduced this response. The combination of PEG-catalase and tempol did not alter the contractile response to PE in both groups. HHcy increased O2(-) generation and SOD activity, whereas H2O2 concentration was reduced. Finally, HHcy did not alter catalase activity or expression of α-actin.
  
  
  CONCLUSIONS
  The major new finding from this study is that HHcy induced a marked increase in PE-induced contraction in rat corpus cavernosum by a mechanism that involves increased O2(-) generation and it could play a role in the pathogenesis of erectile dysfunction associated with HHcy.
authors.affiliation: Departament of Pharmacology, Faculdade de Medicina de Ribeirão Preto, Ribeirão Preto, SP, Brazil.
authors.forename: Hariane
authors.initials: H
authors.lastname: Côco
authors.affiliation: Laboratory of Vascular Injury, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Ribeirão Preto, SP, Brazil.
authors.forename: Larissa
authors.initials: L
authors.lastname: Pernomian
authors.affiliation: Departament of Pharmacology, Faculdade de Medicina de Ribeirão Preto, Ribeirão Preto, SP, Brazil.
authors.forename: Katia C
authors.initials: KC
authors.lastname: Marchi
authors.affiliation: Laboratory of Vascular Injury, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Ribeirão Preto, SP, Brazil.
authors.forename: Mayara S
authors.initials: MS
authors.lastname: Gomes
authors.affiliation: Department of Pathology and Legal Medicine, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Cláudia R
authors.initials: CR
authors.lastname: de Andrade
authors.affiliation: Nucleus of Applied Bioprospection and Molecular Research, Faculdades Inta, Fortaleza, CE, Brazil.
authors.forename: Leandra N Z
authors.initials: LN
authors.lastname: Ramalho
authors.affiliation: Laboratory of Pharmacology, Escola de Enfermagem de Ribeirão Preto, Ribeirão Preto, SP, Brazil.
authors.forename: Carlos R
authors.initials: CR
authors.lastname: Tirapelli
authors.affiliation: Laboratory of Vascular Injury, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Ribeirão Preto, SP, Brazil.
authors.forename: Ana M
authors.initials: AM
authors.lastname: de Oliveira
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D002374:Catalase / Q000378:metabolism; D007172:Erectile Dysfunction / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism; D020138:Hyperhomocysteinemia / Q000378:metabolism*; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology; D009130:Muscle, Smooth / Q000187:drug effects / Q000378:metabolism; D010413:Penis / Q000187:drug effects / Q000378:metabolism*; D010656:Phenylephrine / Q000494:pharmacology; D011092:Polyethylene Glycols / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D017382:Reactive Oxygen Species / Q000378:metabolism*; D018340:Receptors, Adrenergic, alpha-1 / Q000378:metabolism*; D013481:Superoxides / Q000378:metabolism
chemical_list: D000199:Actins; D017382:Reactive Oxygen Species; D018340:Receptors, Adrenergic, alpha-1; C070295:catalase-polyethylene glycol; D013481:Superoxides; D010656:Phenylephrine; D011092:Polyethylene Glycols; D006861:Hydrogen Peroxide; D002374:Catalase
keywords: corpus cavernosum; hyperhomocysteinaemia; α1-adrenergic agonist and reactive oxygen species