In vitro characterization of prostanoid EP-receptors in the non-pregnant human myometrium.
1. Prostaglandin receptors of the PGE type have been characterized in the non-pregnant human myometrium in vitro according to the scheme of Coleman et al. (1984) by use of the agonists PGE2, sulprostone, rioprostil, AY23626, butaprost, misoprostol, 16,16-dimethylprostaglandin E2, enprostil and iloprost, and, the antagonist AH6809. 2. All prostanoids tested were active in non-pregnant human myometrium either as stimulators and/or inhibitors of spontaneous activity or both. Biphasic responses to PGE2 indicate that at least two receptor types of the EP-receptor exist, one mediating relaxation and the other mediating contraction. 3. Further evidence for the EP-receptor mediating excitation and relaxation was provided by the action of the EP2-/EP3-receptor selective prostanoids rioprostil, AY23626 and misoprostol, and the EP1-/EP2-receptor selective agonist 16,16-dimethylprostaglandin E2. 4. Butaprost, an EP2-receptor selective agonist, produced potent inhibition of spontaneous activity in the tissue which was generally longer-lasting than that evoked by the natural prostanoid PGE2. 5. The EP1-/EP3-receptor selective agonist sulprostone and the EP3-receptor agonist enprostil produced potent contractile responses supporting the presence of contractile EP3-receptors in the non-pregnant human myometrium in vitro. 6. The EP1-/IP-receptor selective agonist, iloprost, produced mixed responses in non-pregnant human myometrium. The contractile response was inhibited by the EP1-receptor antagonist AH6809. However, responses to the EP1-/EP3-receptor selective agonist sulprostone were unaffected by AH6809 which may indicate that only a small population of EP1-receptors is present. 7. Therefore it would seem that a heterogeneous population of EP-receptors is present in the non-pregnant human myometrium.
Senior
J
J
Postgraduate Studies in Pharmacology, University of Bradford.
Marshall
K
K
Sangha
R
R
Baxter
G S
GS
Clayton
J K
JK
D015232:Dinoprostone / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D016285:Iloprost / Q000494:pharmacology; D066298:In Vitro Techniques; D016595:Misoprostol / Q000494:pharmacology; D009215:Myometrium / Q000187:drug effects* / Q000502:physiology; D018078:Receptors, Prostaglandin E / Q000032:analysis / Q000187:drug effects*; D016630:Rioprostil / Q000494:pharmacology; D014966:Xanthenes / Q000494:pharmacology; D044004:Xanthones
D018078:Receptors, Prostaglandin E; D014966:Xanthenes; D044004:Xanthones; D016595:Misoprostol; C053876:6-isopropoxy-9-oxoxanthene-2-carboxylic acid; D016630:Rioprostil; D016285:Iloprost; D015232:Dinoprostone