Abstract
Voiding dysfunctions, including increased voiding frequency, urgency, or incontinence, are prevalent in the postmenopausal population. β3-Adrenergic receptor (β3AR) agonists, which relax bladder smooth muscle, are being developed to treat these conditions. We utilized the rat ovariectomy (OVX) model to investigate the effect of ovarian hormone depletion on bladder function and the potential for β3AR agonists to treat bladder hyperactivity in this setting. OVX increased voiding frequency and decreased bladder capacity by ∼25% in awake rats and induced irregular cystometrograms in urethane-anesthetized rats. Reverse transcription-polymerase chain reaction revealed three βARs subtypes (β1,2,3) in bladder tissue, and immunostaining indicated β3AR localization in urothelium and detrusor. Receptor expression was not different in OVX and SHAM rats. The β3AR agonist selectivity of BRL37344 [(±)-(R*,R*)-[4-[2-[[2-(3-chlorophenyl)-2-hydroxyethyl]amino]propyl]phenoxy]acetic acid sodium hydrate], TAK-677 [(3-((2R)-(((2R)-(3-chlorophenyl)-2-hydroxyethyl)amino)propyl)-1H-indol-7-yloxy)acetic acid], and FK175 [acetic acid, 2-[[(8S)-8-[[(2R)-2-(3-chlorophenyl)-2-hydroxyethyl]amino]-6,7,8,9-tetrahydro-5H-benzocyclohepten-2-yl]oxy], ethyl ester, hydrochloride] was confirmed by examining the relative potency for elevation of cAMP in CHOK1 cells overexpressing the various rat βARs. Intravenous injection of each of the β3AR agonists (0.1–500 μg/kg) in anesthetized rats decreased voiding frequency, bladder pressure, and amplitude of bladder contractions. In bladder strips, β3AR agonists (10-12-10-4 M) decreased baseline tone and reduced spontaneous contractions. BRL37344 (5 mg/kg) and TAK-677 (5 mg/kg) injected intraperitoneally in awake rats decreased voiding frequency by 40 to 70%. These effects were not altered by OVX. The results indicate that OVX-induced bladder dysfunction, including decreased bladder capacity and increased voiding frequency, is not associated with changes in β3AR expression or the bladder inhibitory effects of β3AR agonists. This suggests that β3AR agonists should prove effective for the treatment of overactive bladder symptoms in the postmenopausal population.
Footnotes
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This work was supported in part by Procter & Gamble Pharmaceuticals, Incorporated; the American Urology Association [Research Scholar Award] (to F.A.K.); and the National Institutes of Health National Institute of Diabetes and Digestive and Kidney Diseases [Grant DK49430].
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Preliminary findings have been published in abstract form: Kullmann FA, Limberg BJ, Shah M, Contract D, Downs TR, Wos JA, Rosenbaum JS, and de Groat WC (2008) Effects of beta3 adrenergic receptor activation in rat urinary bladder after ovariectomy; 2008 Society for Neuroscience Meeting; 2008 Nov 15–19; Washington, DC. Society for Neuroscience, Washington, DC.
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Article, publication date, and citation information can be found at http://jpet.aspetjournals.org.
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doi:10.1124/jpet.109.155010.
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ABBREVIATIONS: LUT, lower urinary tract; βAR, β-adrenergic receptor; OAB, overactive bladder; OVX, ovariectomy; SHAM, sham surgery; RB, retired breeders; SD, Sprague-Dawley; CMG, continuous infusion cystometry; ICI, intercontraction interval; IHC, immunohistochemistry; A, amplitude of contractions; BP, baseline bladder pressure; PTh, pressure threshold; CHOK1, Chinese hamster ovary cells; NVC, nonvoiding contraction; ACh, acetylcholine; mAChR, muscarinic acetylcholine receptor; BRL37344, (±)-(R*,R*)-[4-[2-[[2-(3-chlorophenyl)-2-hydroxyethyl]-amino]propyl]phenoxy]acetic acid sodium hydrate; TAK-677, (3-((2R)-(((2R)-(3-chlorophenyl)-2-hydroxyethyl)amino)propyl)-1H-indol-7-yloxy)acetic acid; SR59230A, oxalate salt, 3-(2-ethylphenoxy)-1[(1S)-1,2,3,4-tetrahydronaphth-1-ylamino]-(2S)-2-propanol oxalate; ICI 118551, (±)-1-[2,3-(dihydro-7-methyl-1H-inden-4-yl)oxy]-3-[(1-methylethyl)amino]-2-butanol hydrochloride; CL316243, disodium 5-[(2R)-2-[[(2R)-2-(3-chlorophenyl)-2-hydroxyethyl]amino]propyl]-1,3-benzo dioxole-2,2-dicarboxylate; YM178, (R)-2-(2-aminothiazol-4-yl)-4′-{2-[(2-hydroxy-2-phenylethyl)amino]ethyl} acetanilide; CGP12177, 4-[3-[(1,1-dimethylethyl)-amino]-2-hydroxypropoxy]-1,3-dihydro-2H-benzimidazol-2-one hydrochloride; DMSO, dimethyl sulfoxide; BSA, bovine serum albumin; PCR, polymerase chain reaction; r, rat; h, human; ANOVA, analysis of variance; c/w, cells/well; V, virgin; FK-175, acetic acid, 2-[[(8S)-8-[[(2R)-2-(3-chlorophenyl)-2-hydroxyethyl]amino]-6,7,8,9-tetrahydro-5H-benzocyclohepten-2-yl]oxy], ethyl ester, hydrochloride; FAM, fluorescein amidite; [125I]CYP, iodocyanopindolol; qPCR, quantitative polymerase chain reaction.
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↵ The online version of this article (available at http://jpet.aspetjournals.org) contains supplemental material.
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↵1 Current affiliation: Urogenix/Astellas, Durham, North Carolina.
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↵2 Current affiliation: CincyTechUSA, Cincinnati, Ohio.
- Received April 9, 2009.
- Accepted June 9, 2009.
- The American Society for Pharmacology and Experimental Therapeutics
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