title: Differential effect of calcium and Bay K 8644 on the inhibitory action of estrogens in the rat uterus.
abstract: 1. The effects of the estrogens estradiol (E2, 10(-7) to 3 x 10(-5) M) and diethylstilbestrol (DES, 10(-7) to 3 x 10(-6) M) on tonic contractions of the rat uterus induced by KCl and CaCl2 have been studied. 2. E2 and DES relaxed, in a dose-dependent way, the tonic contraction induced by KCl (60 mM) (IC50: 5.16 +/- 1.49 x 10(-6) and 4.51 +/- 0.03 x 10(-7) M); the tonic contraction induced by CaCl2 (3 mM) in the rat uterus incubated in depolarizing Krebs (127 mM of K+) have also been relaxed (IC50: 8.6 +/- 0.03 x 10(-7) and 2.56 +/- 0.07 x 10 M) by both drugs. 3. The CaCl2 (0.1 to 10 mM) counteracted the relaxing effect of E2 and DES, respectively, up to 28.13 +/- 10.2% and 34.71 +/- 11.5%, on KCl-induced contractions, and up to 126.36 +/- 19.35% and 95.8 +/- 16.3% on CaCl2-induced contractions. 4. Bay K 8644 (10(-10) to 10(-6) M) reversed the relaxing effect of E2 and DES, respectively, up to 42.49 +/- 2.28% and 43.31 +/- 3.59% on KCl-induced contractions, and up to 21.73 +/- 4.16% and 75.97 +/- 9.63% on CaCl2-induced contractions. 5. Propranolol (10(-6) M) did not modify the relaxing effect of E2 or DES on CaCl2-induced contractions.
authors.affiliation: Departamento de Medicina, Facultad de Medicina, Universidad de Oviedo, Spain.
authors.forename: A I
authors.initials: AI
authors.lastname: Fernandez
authors.forename: V
authors.initials: V
authors.lastname: Martinez
authors.forename: B
authors.initials: B
authors.lastname: Cantabrana
authors.forename: A
authors.initials: A
authors.lastname: Hidalgo
mesh_terms: D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D002122:Calcium Chloride / Q000494:pharmacology; D004054:Diethylstilbestrol / Q000494:pharmacology; D004958:Estradiol / Q000494:pharmacology; D004965:Estrogen Antagonists / Q000494:pharmacology; D004967:Estrogens / Q000494:pharmacology*; D005260:Female; D066298:In Vitro Techniques; D011189:Potassium Chloride / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D014590:Uterine Contraction / Q000187:drug effects; D014599:Uterus / Q000187:drug effects*
chemical_list: D004965:Estrogen Antagonists; D004967:Estrogens; D004958:Estradiol; D011189:Potassium Chloride; D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; D004054:Diethylstilbestrol; D011433:Propranolol; D002122:Calcium Chloride; D002118:Calcium