title: Contractions of the mouse prostate elicited by acetylcholine are mediated by M(3) muscarinic receptors.
abstract: Increased smooth muscle tone in the human prostate contributes to the symptoms associated with benign prostatic hyperplasia. In the mouse prostate gland, cholinergic innervation is responsible for a component of the nerve-mediated contractile response. This study investigates the muscarinic receptor subtype responsible for the cholinergic contractile response in the mouse prostate gland. To characterize the muscarinic receptor subtype, mouse prostates taken from wild-type or M(3) muscarinic receptor knockout mice were mounted in organ baths. The isometric force that tissues developed in response to electrical-field stimulation or exogenously applied cholinergic agonists in the presence or absence of a range of muscarinic receptor antagonists was evaluated. Carbachol elicited reproducible and concentration-dependent contractions of the isolated mouse prostate, which were antagonized by the presence of muscarinic receptor antagonists. Calculation of antagonist affinities (pA(2) values) indicated a rank order of antagonist potencies in the mouse prostate of: darifenacin (9.08) = atropine (9.07) = 1,1-dimethyl-4-diphenylacetoxypiperidinium iodide (9.02) > cyclohexyl-hydroxy-phenyl-(3-piperidin-1-ylpropyl)silane (7.85) > cyclohexyl-(4-fluorophenyl)-hydroxy-(3-piperidin-1-ylpropyl)silane (7.39) > himbacine (7.19) > pirenzipine (6.88) > methoctramine (6.20). Furthermore, genetic deletion of the M(3) muscarinic receptor inhibited prostatic contractions to electrical-field stimulation or exogenous administration of acetylcholine. In this study we identified that the cholinergic component of contraction in the mouse prostate is mediated by the M(3) muscarinic receptor subtype. Pharmacological antagonism of the M(3) muscarinic receptor may be a beneficial additional target for the treatment of benign prostatic hyperplasia in the human prostate gland.
authors: Medicinal Chemistry and Drug Action, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Victoria 3052, Australia.
authors: Carl W
authors: CW
authors: White
authors: Jennifer L
authors: JL
authors: Short
authors: John M
authors: JM
authors: Haynes
authors: Minoru
authors: M
authors: Matsui
authors: Sabatino
authors: S
authors: Ventura
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology*; D058668:Adrenergic alpha-1 Receptor Antagonists / Q000494:pharmacology; D000818:Animals; D001572:Benzofurans / Q000494:pharmacology; D001835:Body Weight / Q000187:drug effects; D002217:Carbachol / Q000494:pharmacology; D018679:Cholinergic Agonists / Q000494:pharmacology*; D004347:Drug Interactions; D008297:Male; D008464:Mecamylamine / Q000494:pharmacology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D018727:Muscarinic Antagonists / Q000494:pharmacology*; D009119:Muscle Contraction / Q000187:drug effects* / Q000502:physiology; D018733:Nicotinic Antagonists / Q000494:pharmacology*; D011224:Prazosin / Q000494:pharmacology; D011467:Prostate / Q000187:drug effects / Q000502:physiology*; D011759:Pyrrolidines / Q000494:pharmacology; D043587:Receptor, Muscarinic M3 / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism*
chemical_list: D058668:Adrenergic alpha-1 Receptor Antagonists; D001572:Benzofurans; D018679:Cholinergic Agonists; D018727:Muscarinic Antagonists; D018733:Nicotinic Antagonists; D011759:Pyrrolidines; D043587:Receptor, Muscarinic M3; D008464:Mecamylamine; D002217:Carbachol; C101207:darifenacin; D000109:Acetylcholine; D011224:Prazosin