title: The effects of 17β-oestradiol on increased α(1)-adrenergic vascular reactivity induced by prolonged ovarian hormone deprivation: the role of voltage-dependent L-type Ca channels.
abstract: The present study investigated the hypothesis that the duration of ovarian hormone deprivation before reintroduction of oestrogen affects the role of oestrogen as a mediator of the contractile function of α(1)-adrenergic receptors. Rats underwent ovariectomy (OVX) or were sham-operated, and the OVX rats were treated with vehicle (corn oil) or 17β-oestradiol (E(2)) for 5 days either 10, 28 or 60 days after OVX. The OVX increased phenylephrine- and Ca(2+)-induced contractions. Interestingly, the phenylephrine-induced contractions were increased at each of the three time points, whereas the Ca(2+)-induced contractions were only increased in the 60-day group. E(2) had biphasic effects on phenylephrine- and Ca(2+)-induced contractility. Indeed, E(2) increased contractions in the 10-day group and diminished contractions in the other groups (the increased contractions were avoided by verapamil). These results indicate that E(2) controls α(1)-adrenergic receptor-mediated contractility through effects on L-type Ca(2+) channels in a way that depends on the timing in which the treatment with E(2) is initiated.
authors.affiliation: Instituto de Investigaciones Químico-Biológicas de la UMSNH, Morelia, México. ivalencia@ipn.mx
authors.forename: Ignacio
authors.initials: I
authors.lastname: Valencia-Hernández
authors.forename: José Antonio
authors.initials: JA
authors.lastname: Reyes-Ramírez
authors.forename: Héctor
authors.initials: H
authors.lastname: Urquiza-Marín
authors.forename: Blanca
authors.initials: B
authors.lastname: Nateras-Marín
authors.forename: José Carlos
authors.initials: JC
authors.lastname: Villegas-Bedolla
authors.forename: Daniel
authors.initials: D
authors.lastname: Godínez-Hernández
mesh_terms: D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects / Q000502:physiology; D002118:Calcium / Q000494:pharmacology; D002121:Calcium Channel Blockers / Q000494:pharmacology; D020746:Calcium Channels, L-Type / Q000502:physiology*; D004958:Estradiol / Q000008:administration & dosage*; D004967:Estrogens / Q000008:administration & dosage*; D005260:Female; D066298:In Vitro Techniques; D010052:Ovariectomy; D010656:Phenylephrine / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D018340:Receptors, Adrenergic, alpha-1 / Q000502:physiology*; D014661:Vasoconstriction / Q000187:drug effects; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014665:Vasodilator Agents; D014700:Verapamil / Q000494:pharmacology
chemical_list: D002121:Calcium Channel Blockers; D020746:Calcium Channels, L-Type; D004967:Estrogens; D018340:Receptors, Adrenergic, alpha-1; D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D010656:Phenylephrine; D004958:Estradiol; D014700:Verapamil; D002118:Calcium