Inhibitory effects of Rb+ on the responses to levcromakalim and P1060 in the isolated human myometrium.
The mechanoinhibitory effects of two structurally dissimilar K+ channel openers, levcromakalim and P1060, and verapamil were compared in strips of human myometrium bathed in either K-PSS (normal Krebs solution) or Rb-PSS (K+ salts replaced by Rb+ equivalents). In Rb-PSS the effects of levcromakalim and P1060 on amplitude and frequency of spontaneous contractions were inhibited by more than 20- and 138-fold, respectively, whereas those of verapamil were unaltered. These results indicate that K+ channel openers possess Rb-sensitive and Rb-insensitive mechanoinhibitory actions on the human uterus, the former being more important in the effects of P1060 than levcromakalim.
Criddle
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DN
Departamento de Farmacologia, Universidade do Estado do Rio de Janeiro, Brazil.
de Moura
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RS
D001578:Benzopyrans / Q000494:pharmacology*; D019806:Cromakalim; D005260:Female; D006146:Guanidines / Q000494:pharmacology*; D006801:Humans; D066298:In Vitro Techniques; D015221:Potassium Channels / Q000187:drug effects*; D011758:Pyrroles / Q000494:pharmacology*; D012413:Rubidium / Q000494:pharmacology*; D014590:Uterine Contraction / Q000187:drug effects*; D014700:Verapamil / Q000494:pharmacology
D001578:Benzopyrans; D006146:Guanidines; D015221:Potassium Channels; D011758:Pyrroles; D019806:Cromakalim; C058754:N'-cyano-N-(3-pyridyl)-N''-(t-butyl)guanidine; D014700:Verapamil; D012413:Rubidium