Hormonal modulation of benzodiazepines' actions on rat isolated uterus. 1996

M K Yiu, and Y W Kwan, and M P Ngan
Department of Pharmacology, Faculty of Medicine, Chinese University of Hong Kong, Shatin, New Territories, Hong Kong.

Effects of various benzodiazepines were investigated in ovariectomized rat isolated uterus which had been chronically pre-treated with different female sex hormones: oestrogen, progesterone and oestrogen + progesterone. Uteri obtained from all groups developed a spontaneous, rhythmic activity. The spontaneous activity observed in control uterus was either inhibited in a concentration-dependent manner by diazepam, 4'-chlorodiazepam, clonazepam or 1-(2-chlorophenyl)-N-methyl-N-(1-methylpropyl)-3-isoquinolinecarboxam ide (PK 11195), or was abolished in [Ca2+]o-free solution. Diazepam, 4'-chlorodiazepam, clonazepam and PK 11195 all caused a concentration-dependent relaxation of the [K+]o-pre-contracted uterus with the relative order of potency: PK 11195 > 4'-chlorodiazepam > diazepam > clonazepam. Administration of [Ca2+]o (1 microM to 10 mM) caused a concentration-dependent contraction of uterus, bathed in [Ca2+]o-free physiological salt solution obtained from different pre-treatment groups. Incubation with different concentrations (microM) of diazepam, 4'-chlorodiazepam, clonazepam and PK 11195 caused a decrease in response to [Ca2+]o-induced contraction in all groups of rat uteri. These results indicate that micromolar benzodiazepine binding sites exist in rat uterus. Diazepam, 4'-chlorodiazepam, clonazepam and PK 11195 caused relaxation of pre-contracted rat uterus and this effect may involve the inhibition of influx of [Ca2+]o and the relaxing effects of different benzodiazepines observed in this study can be modulated by pre-treatment with different female hormones.

UI MeSH Term Description Entries
D007546 Isoquinolines A group of compounds with the heterocyclic ring structure of benzo(c)pyridine. The ring structure is characteristic of the group of opium alkaloids such as papaverine. (From Stedman, 25th ed)
D010052 Ovariectomy The surgical removal of one or both ovaries. Castration, Female,Oophorectomy,Bilateral Ovariectomy,Bilateral Ovariectomies,Castrations, Female,Female Castration,Female Castrations,Oophorectomies,Ovariectomies,Ovariectomies, Bilateral,Ovariectomy, Bilateral
D011374 Progesterone The major progestational steroid that is secreted primarily by the CORPUS LUTEUM and the PLACENTA. Progesterone acts on the UTERUS, the MAMMARY GLANDS and the BRAIN. It is required in EMBRYO IMPLANTATION; PREGNANCY maintenance, and the development of mammary tissue for MILK production. Progesterone, converted from PREGNENOLONE, also serves as an intermediate in the biosynthesis of GONADAL STEROID HORMONES and adrenal CORTICOSTEROIDS. Pregnenedione,Progesterone, (13 alpha,17 alpha)-(+-)-Isomer,Progesterone, (17 alpha)-Isomer,Progesterone, (9 beta,10 alpha)-Isomer
D011963 Receptors, GABA-A Cell surface proteins which bind GAMMA-AMINOBUTYRIC ACID and contain an integral membrane chloride channel. Each receptor is assembled as a pentamer from a pool of at least 19 different possible subunits. The receptors belong to a superfamily that share a common CYSTEINE loop. Benzodiazepine-Gaba Receptors,GABA-A Receptors,Receptors, Benzodiazepine,Receptors, Benzodiazepine-GABA,Receptors, Diazepam,Receptors, GABA-Benzodiazepine,Receptors, Muscimol,Benzodiazepine Receptor,Benzodiazepine Receptors,Benzodiazepine-GABA Receptor,Diazepam Receptor,Diazepam Receptors,GABA(A) Receptor,GABA-A Receptor,GABA-A Receptor alpha Subunit,GABA-A Receptor beta Subunit,GABA-A Receptor delta Subunit,GABA-A Receptor epsilon Subunit,GABA-A Receptor gamma Subunit,GABA-A Receptor rho Subunit,GABA-Benzodiazepine Receptor,GABA-Benzodiazepine Receptors,Muscimol Receptor,Muscimol Receptors,delta Subunit, GABA-A Receptor,epsilon Subunit, GABA-A Receptor,gamma-Aminobutyric Acid Subtype A Receptors,Benzodiazepine GABA Receptor,Benzodiazepine Gaba Receptors,GABA A Receptor,GABA A Receptor alpha Subunit,GABA A Receptor beta Subunit,GABA A Receptor delta Subunit,GABA A Receptor epsilon Subunit,GABA A Receptor gamma Subunit,GABA A Receptor rho Subunit,GABA A Receptors,GABA Benzodiazepine Receptor,GABA Benzodiazepine Receptors,Receptor, Benzodiazepine,Receptor, Benzodiazepine-GABA,Receptor, Diazepam,Receptor, GABA-A,Receptor, GABA-Benzodiazepine,Receptor, Muscimol,Receptors, Benzodiazepine GABA,Receptors, GABA A,Receptors, GABA Benzodiazepine,delta Subunit, GABA A Receptor,epsilon Subunit, GABA A Receptor,gamma Aminobutyric Acid Subtype A Receptors
D002998 Clonazepam An anticonvulsant used for several types of seizures, including myotonic or atonic seizures, photosensitive epilepsy, and absence seizures, although tolerance may develop. It is seldom effective in generalized tonic-clonic or partial seizures. The mechanism of action appears to involve the enhancement of GAMMA-AMINOBUTYRIC ACID receptor responses. 2H-1,4-Benzodiazepin-2-one, 5-(2-chlorophenyl)-1,3-dihydro-7-nitro-,Klonopin,Antelepsin,Rivotril,Ro 5-4023,Ro 54023
D003975 Diazepam A benzodiazepine with anticonvulsant, anxiolytic, sedative, muscle relaxant, and amnesic properties and a long duration of action. Its actions are mediated by enhancement of GAMMA-AMINOBUTYRIC ACID activity. 7-Chloro-1,3-dihydro-1-methyl-5-phenyl-2H-1,4-benzodiazepin-2-one,Apaurin,Diazemuls,Faustan,Relanium,Seduxen,Sibazon,Stesolid,Valium
D004305 Dose-Response Relationship, Drug The relationship between the dose of an administered drug and the response of the organism to the drug. Dose Response Relationship, Drug,Dose-Response Relationships, Drug,Drug Dose-Response Relationship,Drug Dose-Response Relationships,Relationship, Drug Dose-Response,Relationships, Drug Dose-Response
D004338 Drug Combinations Single preparations containing two or more active agents, for the purpose of their concurrent administration as a fixed dose mixture. Drug Combination,Combination, Drug,Combinations, Drug
D004967 Estrogens Compounds that interact with ESTROGEN RECEPTORS in target tissues to bring about the effects similar to those of ESTRADIOL. Estrogens stimulate the female reproductive organs, and the development of secondary female SEX CHARACTERISTICS. Estrogenic chemicals include natural, synthetic, steroidal, or non-steroidal compounds. Estrogen,Estrogen Effect,Estrogen Effects,Estrogen Receptor Agonists,Estrogenic Agents,Estrogenic Compounds,Estrogenic Effect,Estrogenic Effects,Agents, Estrogenic,Agonists, Estrogen Receptor,Compounds, Estrogenic,Effects, Estrogen,Effects, Estrogenic,Receptor Agonists, Estrogen
D005260 Female Females

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