Adrenoceptors mediating contraction in the human uterine artery.
Pharmacological characterization of adrenoceptors mediating smooth muscle contraction was performed in isolated preparations from the human uterine artery. The mixed alpha 1- and alpha 2-adrenergic agonist, noradrenaline (NA) and the selective alpha 1-agonists, phenylephrine and methoxamine, all contracted the smooth muscle preparations in a concentration-dependent manner. The responses were antagonized competitively by the selective alpha 1-antagonist, prazosin, yielding pA2 values for the three agonists (8.33-9.08) typical for an interaction with alpha 1-receptors. The alpha 2-selective receptor agonists, clonidine and BHT 920, did not exert any contractile effects in the isolated uterine arteries, and the alpha 2-adrenergic antagonist, yohimbine, counteracted the contractile effect of NA only at high concentrations. The concentration-response curve for NA was unaffected by the alpha 2-selective antagonists, rauwolscine and idazoxan. The results suggest that the postjunctional contractile receptors in the human uterine artery primarily are of the alpha 1 type, and give no evidence for any substantial involvement of alpha 2-receptors in this important tributary vessel of the human female reproductive tract.
Stjernquist
M
M
Department of Obstetrics and Gynaecology, University of Lund, General Hospital, Malmö, Sweden.
Owman
C
C
D000328:Adult; D000368:Aged; D001158:Arteries / Q000502:physiology; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D008729:Methoxamine / Q000494:pharmacology; D008875:Middle Aged; D009119:Muscle Contraction / Q000187:drug effects*; D009131:Muscle, Smooth, Vascular / Q000502:physiology; D009638:Norepinephrine / Q000494:pharmacology; D010656:Phenylephrine / Q000494:pharmacology; D011941:Receptors, Adrenergic / Q000502:physiology*; D014599:Uterus / Q000098:blood supply*
D011941:Receptors, Adrenergic; D010656:Phenylephrine; D008729:Methoxamine; D009638:Norepinephrine