title: Muscarinic receptors mediating contraction of female mouse urinary bladder: effects of oestrogen.
abstract: Muscarinic receptors mediating contraction of bladder detrusor muscle from female mice were examined. Mice were untreated (A) or treated with oestradiol cypionate (200 microg/kg) 24 h (B) or 96 h (C) before experimentation, or were pregnant (day 17) (D). Saturation radioligand binding experiments using [(3)H]quinuclidinyl benzilate ([(3)H] QNB) indicated similar muscarinic receptor densities and affinities in bladders from groups A and B. Neither oestrogen treatment nor pregnancy altered pD(2) estimates for methacholine. Maximum responses to methacholine and high-K(+) physiological salt solution (KPSS) were significantly greater (P<0.05) in tissues from groups C and D than in A and B. Potencies of other muscarinic receptor agonists were similar in groups A and B with an order of acetylcholine plus physostigmine (10 microM) approximately methacholine plus physostigmine (10 microM)>methacholine approximately acetylcholine>bethanechol. Antagonist pK(B) estimates were similar in bladders from groups A and B with a rank order of: atropine>/=4-diphenyl acetoxy-N-methyl piperidine methiodide>parafluorohexahydrosiladifenidol approximately pirenzepine>himbacine, implicating muscarinic M(1) and/or M(5) as well as muscarinic M(3) receptors in mediating methacholine-induced bladder contraction.
authors.affiliation: Department of Pharmacology, Monash University, Clayton 3800, Victoria, Australia.
authors.forename: Sherie
authors.initials: S
authors.lastname: Ma
authors.forename: Margot E
authors.initials: ME
authors.lastname: Story
authors.forename: Jocelyn N
authors.initials: JN
authors.lastname: Pennefather
mesh_terms: D000818:Animals; D001285:Atropine / Q000494:pharmacology; D004967:Estrogens / Q000494:pharmacology*; D005260:Female; D066298:In Vitro Techniques; D016210:Methacholine Chloride / Q000494:pharmacology; D051379:Mice; D008807:Mice, Inbred BALB C; D018721:Muscarinic Agonists / Q000494:pharmacology; D018727:Muscarinic Antagonists / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects*; D009929:Organ Size / Q000187:drug effects; D011247:Pregnancy; D011869:Radioligand Assay; D011976:Receptors, Muscarinic / Q000187:drug effects* / Q000502:physiology*; D001743:Urinary Bladder / Q000187:drug effects*; D014621:Vagina / Q000166:cytology / Q000187:drug effects
chemical_list: D004967:Estrogens; D018721:Muscarinic Agonists; D018727:Muscarinic Antagonists; D011976:Receptors, Muscarinic; D016210:Methacholine Chloride; D001285:Atropine