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Witte LPW, de Haas N, Mammen M, Stangeland EL, Steinfeld T, Aiyar J, Michel MC. Muscarinic receptor subtypes and signalling involved in the attenuation of isoprenaline-induced rat urinary bladder relaxation. Naunyn Schmiedebergs Arch Pharmacol 2011; 384:555-63. [PMID: 21947231 PMCID: PMC3220825 DOI: 10.1007/s00210-011-0689-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2011] [Accepted: 08/26/2011] [Indexed: 12/16/2022]
Abstract
β-Adrenoceptors are important mediators of smooth muscle relaxation in the urinary bladder, but the concomitant presence of a muscarinic agonist, e.g., carbachol, can attenuate relaxation responses by reducing potency and/or efficacy of β-adrenoceptor agonists such as isoprenaline. Therefore, the present study was designed to explore the subtypes and signalling pathways of muscarinic receptors involved in the attenuation of isoprenaline-induced isolated rat detrusor preparations using novel subtype-selective receptor ligands. In radioligand binding studies, we characterized BZI to be a M3-sparing muscarinic agonist, providing selective M2 stimulation in rat bladder, and THRX-182087 as a highly M2-selective antagonist. The use of BZI and of THRX-182087 in the presence of carbachol enabled experimental conditions with a selective stimulation of only M2 or M3 receptors, respectively. Confirming previous findings, carbachol attenuated isoprenaline-induced detrusor relaxation. M2-selective stimulation partly mimicked this attenuation, indicating that both M2 and M3 receptors are involved. During M3-selective stimulation, the attenuation of isoprenaline responses was reduced by the phospholipase C inhibitor U 73,122 but not by the protein kinase C inhibitor chelerythrine. We conclude that both M2 and M3 receptors contribute to attenuation of β-adrenoceptor-mediated relaxation of rat urinary bladder; the signal transduction pathway involved in the M3 component of this attenuation differs from that mediating direct contractile effects of M3 receptors.
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Affiliation(s)
- Lambertus P W Witte
- Depts. of Pharmacology and Pharmacotherapy and of Urology, Academic Medical Center, Amsterdam, The Netherlands
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2
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Abstract
This article is a review of the current and past literature on medical management of the neurogenic bladder, with a particular focus on spinal cord injury and multiple sclerosis. The use of antimuscarinics, αα-blocker, and tricyclic antidepressants and their combined use are discussed along with new therapies in human and animal trials.
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Affiliation(s)
- Anne P Cameron
- Department of Urology, University of Michigan, 3875 Taubman Center, 1500 East Medical Center Drive, Ann Arbor, MI 48109-5330, USA.
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3
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Braverman AS. Alterations in muscarinic receptor subtype function in the bladder. CURRENT BLADDER DYSFUNCTION REPORTS 2009. [DOI: 10.1007/s11884-009-0007-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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4
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Braverman AS, Miller LS, Vegesna AK, Tiwana MI, Tallarida RJ, Ruggieri MR. Quantitation of the contractile response mediated by two receptors: M2 and M3 muscarinic receptor-mediated contractions of human gastroesophageal smooth muscle. J Pharmacol Exp Ther 2009; 329:218-24. [PMID: 19126780 DOI: 10.1124/jpet.108.148106] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Although muscarinic receptors are known to mediate tonic contraction of human gastrointestinal tract smooth muscle, the receptor subtypes that mediate the tonic contractions are not entirely clear. Whole human stomachs with attached esophagus were procured from organ transplant donors. Cholinergic contractile responses of clasp, sling, lower esophageal circular (LEC), midesophageal circular (MEC), and midesophageal longitudinal (MEL) muscle strips were determined. Sling fibers contracted greater than the other fibers. Total, M(2) and M(3) muscarinic receptor density was determined for each of these dissections by immunoprecipitation. M(2) receptor density is greatest in the sling fibers, followed by clasp, LEC, MEC, and then MEL, whereas M(3) density is greatest in LEC, followed by MEL, MEC, sling, and then clasp. The potency of subtype-selective antagonists to inhibit bethanechol-induced contraction was calculated by Schild analysis to determine which muscarinic receptor subtypes contribute to contraction. The results suggest both M(2) and M(3) receptors mediate contraction in clasp and sling fibers. Thus, this type of analysis in which multiple receptors mediate the contractile response is inappropriate, and an analysis method relating dual occupation of M(2) and M(3) receptors to contraction is presented. Using this new method of analysis, it was found that the M(2) muscarinic receptor plays a greater role in mediating contraction of clasp and sling fibers than in LEC, MEC, and MEL muscles in which the M(3) receptor predominantly mediates contraction.
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Affiliation(s)
- Alan S Braverman
- Department of Urology, Temple University School of Medicine, Philadelphia, PA 19140, USA
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5
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Braverman AS, Tallarida RJ, Ruggieri MR. The use of occupation isoboles for analysis of a response mediated by two receptors: M2 and M3 muscarinic receptor subtype-induced mouse stomach contractions. J Pharmacol Exp Ther 2008; 325:954-60. [PMID: 18339971 DOI: 10.1124/jpet.108.137018] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Smooth muscle contains multiple muscarinic receptor subtypes, including M2 and M3. M2 receptors outnumber M3 receptors. Based on the potency of subtype selective anticholinergics, contraction is mediated by the M3 subtype. However, results from knockout (KO) mice show that the M2 receptor mediates approximately 45% of the contractile response produced by the M3 receptor. The traditional theory of one receptor mediating a response does not allow assessment of interactions between receptors when more than one receptor participates in a response. Our study was performed using a novel analysis method based on dual receptor occupancy to determine how M2 and M3 receptor subtypes interact to mediate contraction in mouse stomach. Cumulative carbachol concentration contractile responses were determined for wild-type, M2-KO, and M3-KO stomach body smooth muscle. Using affinity constants for carbachol at M2 and M3 cholinergic receptors, the concentration values were converted to fractional receptor occupation. The resulting occupation-effect relations showed maximum effects for the M2 and M3 subtypes, respectively. These occupation-effect relations allow determination of the additive (expected) isobole based on this dual occupancy, thereby providing a curve (mathematically derived) for comparison against the experimentally derived value in wild type. The actual values determined experimentally in the wild type were not statistically significantly different from that predicted by the isobole. This confirms that the interaction between these mutually occupied receptors is additive. The new method of analysis also expands the traditional Schild theory that was based on a single receptor type to which the agonist and antagonist bind.
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Affiliation(s)
- Alan S Braverman
- Department of Urology, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, USA
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6
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Ruggieri MR, Braverman AS. Regulation of bladder muscarinic receptor subtypes by experimental pathologies. AUTONOMIC & AUTACOID PHARMACOLOGY 2006; 26:311-25. [PMID: 16879497 PMCID: PMC3275807 DOI: 10.1111/j.1474-8673.2006.00377.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
1 The M3 muscarinic receptor subtype is widely accepted as the receptor on smooth muscle cells that mediates cholinergic contraction of the normal urinary bladder and other smooth muscle tissues, however, we have found that the M2 receptor participates in contraction under certain abnormal conditions. The aim of this study was to determine the effects of various experimental pathologies on the muscarinic receptor subtype mediating urinary bladder contraction. 2 Experimental pathologies resulting in bladder hypertrophy (denervation and outlet obstruction) result in an up-regulation of bladder M2 receptors and a change in the receptor subtype mediating contraction from M3 towards M2. Preventing the denervation-induced bladder hypertrophy by urinary diversion prevents this shift in contractile phenotype indicating that hypertrophy is responsible as opposed to denervation per se. 3 The hypertrophy-induced increase in M2 receptor density and contractile response is accompanied by an increase in the tissue concentrations of mRNA coding for the M2 receptor subtype, however, M3 receptor protein density does not correlate with changes in M3 receptor tissue mRNA concentrations across different experimental pathologies. 4 This shift in contractile phenotype from M3 towards M2 subtype is also observed in aged male Sprague-Dawley rats but not females or either sex of the Fisher344 strain of rats. 5 Four repeated, sequential agonist concentration response curves also cause this shift in contractile phenotype in normal rat bladder strips in vitro, as evidenced by a decrease in the affinity of the M3 selective antagonist p-fluoro-hexahydro-sila-diphenidol (p-F-HHSiD). 6 A similar decrease in the contractile affinity of M3 selective antagonists (darifenacin and p-F-HHSiD) is also observed in bladder specimens from patients with neurogenic bladder as well as certain organ transplant donors. 7 It is concluded that although the M3 receptor subtype predominantly mediates contraction under normal circumstances, the M2 receptor subtype can take over a contractile role when the M3 subtype becomes inactivated by, for example, repeated agonist exposures or bladder hypertrophy. This finding has substantial implications for the clinical treatment of abnormal bladder contractions.
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MESH Headings
- Age Factors
- Animals
- Benzofurans/pharmacology
- Carbachol/pharmacology
- Denervation
- Disease Models, Animal
- Electric Stimulation
- Female
- Gene Expression Regulation
- Humans
- Hypertrophy
- Male
- Muscarinic Agonists/pharmacology
- Muscarinic Antagonists/pharmacology
- Muscle Contraction/drug effects
- Muscle, Smooth/drug effects
- Muscle, Smooth/innervation
- Muscle, Smooth/metabolism
- Muscle, Smooth/pathology
- Piperidines/pharmacology
- Pyrrolidines/pharmacology
- RNA, Messenger/metabolism
- Rats
- Rats, Inbred F344
- Rats, Sprague-Dawley
- Receptor, Muscarinic M2/drug effects
- Receptor, Muscarinic M2/genetics
- Receptor, Muscarinic M2/metabolism
- Receptor, Muscarinic M3/drug effects
- Receptor, Muscarinic M3/genetics
- Receptor, Muscarinic M3/metabolism
- Urinary Bladder/drug effects
- Urinary Bladder/innervation
- Urinary Bladder/metabolism
- Urinary Bladder/pathology
- Urinary Bladder Neck Obstruction/metabolism
- Urinary Bladder Neck Obstruction/pathology
- Urinary Bladder, Neurogenic/metabolism
- Urinary Bladder, Neurogenic/pathology
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Affiliation(s)
- M R Ruggieri
- Department of Urology, Temple University, Philadelphia, PA, USA
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Braverman AS, Ruggieri MR. Muscarinic receptor transcript and protein density in hypertrophied and atrophied rat urinary bladder. Neurourol Urodyn 2006; 25:55-61. [PMID: 16304675 PMCID: PMC3277085 DOI: 10.1002/nau.20180] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
AIMS Our previous studies showed that bladder hypertrophy shifts the muscarinic receptor subtype mediating contraction from M(3) towards M(2) along with increased M(2) and decreased M(3) protein concentration. We quantified mRNA for M(1) through M(5) receptors to determine whether the changes in M(2) and M(3) protein levels was due to changes in transcription. METHODS Bladder hypertrophy was induced by bladder outlet obstruction (BOO), major pelvic ganglion electrocautery (DEN), and major pelvic ganglion decentralization (DEC). Bladder atrophy was induced by ureteral diversion (DIV). Additional groups included denervated and diverted (DEN-DIV), sham operated (SHAM), and normal (NOR) controls. Transcripts were quantified using a multiplex ribonuclease protection assay (RPA) and receptor protein density was determined by immunoprecipitation. Receptor transcripts were expressed per unit total RNA. RESULTS Although all five receptor subtype transcripts were detected in all experimental groups, the densities of M(1), M(4), and M(5) were much lower than for the M(2) and M(3) subtype. There were more M(2) receptor transcripts than all the others, consistent with M(2) protein determinations. M(2) transcripts were significantly increased in DEN and BOO bladders. Surprisingly, M(3) transcripts were also significantly increased in BOO. There was a significant correlation (r=0.98, P<0.001) between protein density and transcript density for the M(2) but not the M(3) receptor among the different experimental groups. CONCLUSIONS Changes in mRNA concentration are reflected by changes in protein density for the M(2) receptor but not for the M(3) receptor. Extrapolation of functional effects from transcript density data is invalid for M(3) mediated bladder contractions.
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Affiliation(s)
- Alan S. Braverman
- Department of Urology, Temple University School of Medicine, Philadelphia, Pennsylvania
| | - Michael R. Ruggieri
- Department of Urology, Temple University School of Medicine, Philadelphia, Pennsylvania
- Department of Pharmacology, Temple University School of Medicine, Philadelphia, Pennsylvania
- Correspondence to: Michael R. Ruggieri, Sr., Temple University School of Medicine, 3400 North Broad Street, 715 OMS, Philadelphia, PA 19140.
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8
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Braverman AS, Doumanian LR, Ruggieri MR. M2 and M3 Muscarinic Receptor Activation of Urinary Bladder Contractile Signal Transduction. II. Denervated Rat Bladder. J Pharmacol Exp Ther 2005; 316:875-80. [PMID: 16243962 DOI: 10.1124/jpet.105.094961] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Normal rat bladder contractions are mediated by the M(3) muscarinic receptor subtype. The M(2) receptor subtype mediates contractions of the denervated, hypertrophied bladder. This study determined signal transduction mechanisms mediating contraction of the denervated rat bladder. Denervated bladder muscle strips were exposed to inhibitors of enzymes thought to be involved in signal transduction in vitro followed by a cumulative carbachol concentration-response curve. Outcome measures were the maximal contraction, the potency of carbachol, and the affinity of darifenacin for inhibition of contraction. Inhibition of phosphoinositide-specific phospholipase C (PI-PLC) with 1-O-octadecyl-2-O-methyl-sn-glycero-3-phosphorylcholine (ET-18-OCH(3)) has no effect on denervated bladder contractions, whereas inhibition of phosphatidyl choline-specific phospholipase C (PC-PLC) with O-tricyclo[5.2.1.02,6]dec-9-yl dithiocarbonate potassium salt (D609) attenuates the carbachol maximum and potency. Inhibition of rho kinase with (R)-(+)-trans-4-(1-aminoethyl)-N-(4-pyridyl)cyclohexanecarboxamide dihydrochloride (Y-27632) reduces carbachol maximum, carbachol potency, and increases darifenacin affinity. Inhibition of rho kinase, protein kinase A (PKA), and protein kinase G (PKG) with 1-(5-isoquinolinesulfonyl)-homopiperazine.HCl (HA-1077) reduces the carbachol maximum and potency. Inhibition of PKC with chelerythrine increases darifenacin affinity, whereas inhibition of rho kinase, PKA, PKG, and protein kinase C (PKC) with 1-(5-isoquinolinesulfonyl)-2-methylpiperazine.2HCl (H7) reduces the carbachol potency while increasing darifenacin affinity. Inhibition of rho kinase, PKA, and PKG with N-[2-(p-bromocinnamylamino)ethyl]-5-isoquinolinesulfonamide.2HCl (H89) increases darifenacin affinity. This study demonstrates that different signal transduction mechanisms mediate the contractile response in the denervated rat bladder than in normal rat bladder. In normal rat bladder, PI-PLC and PC-PLC mediate the contraction, but in denervated bladder only PC-PLC is involved. In the denervated bladder, the rho kinase pathway is more dominant than in normal bladders. PKA seems to mediate a contractile response in normal bladders, whereas it seems to inhibit contraction in denervated bladders.
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MESH Headings
- Animals
- Benzofurans/pharmacology
- Carbachol/pharmacology
- Dose-Response Relationship, Drug
- Enzyme Inhibitors/pharmacology
- Female
- In Vitro Techniques
- Muscarinic Agonists/pharmacology
- Muscarinic Antagonists/pharmacology
- Muscle Contraction/drug effects
- Muscle Denervation
- Muscle, Smooth/drug effects
- Muscle, Smooth/enzymology
- Muscle, Smooth/innervation
- Muscle, Smooth/metabolism
- Pyrrolidines/pharmacology
- Rats
- Rats, Sprague-Dawley
- Receptor, Muscarinic M2/agonists
- Receptor, Muscarinic M2/antagonists & inhibitors
- Receptor, Muscarinic M2/metabolism
- Receptor, Muscarinic M3/agonists
- Receptor, Muscarinic M3/antagonists & inhibitors
- Receptor, Muscarinic M3/metabolism
- Signal Transduction/drug effects
- Urinary Bladder/drug effects
- Urinary Bladder/enzymology
- Urinary Bladder/innervation
- Urinary Bladder/metabolism
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Affiliation(s)
- Alan S Braverman
- Department of Urology, Temple University School of Medicine, Philadelphia, PA 19140, USA
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9
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Pontari MA, Braverman AS, Ruggieri MR. The M2 muscarinic receptor mediates in vitro bladder contractions from patients with neurogenic bladder dysfunction. Am J Physiol Regul Integr Comp Physiol 2004; 286:R874-80. [PMID: 14751843 PMCID: PMC3274770 DOI: 10.1152/ajpregu.00391.2003] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Bladder muscle specimens from seven patients with neurogenic bladder dysfunction were analyzed to determine whether the muscarinic receptor subtype mediating contraction shifts from M(3) to the M(2) subtype as found in the denervated, hypertrophied rat bladder. Seven bladder specimens were analyzed from six female and one male patients. Six of the patients had traumatic cervical spinal cord injuries (C(4)-C(7)), and the other patient had an L(1) congenital myelomeningocele. This was compared with results from bladder specimens obtained from eight organ transplant donors. The affinities of three subtype-selective muscarinic receptor antagonists for inhibition of carbachol-induced contractions were determined. The affinity of the M(3) selective antagonists darifenacin or p-fluoro-hexahydrosiladifenadol (p-F-HHSiD) was determined in six of the seven spinal injury patient specimens. The affinity was consistent with M(2)-mediated contractions in four of these six specimens, intermediate between M(2) and M(3) in one specimen, and within the M(3) range in one specimen. The other specimen, tested only with the M(2) selective antagonist methoctramine, showed an M(3) affinity. In the organ donors, the affinity of p-F-HHSiD was within the M(2) range for six of seven specimens, whereas the affinity of darifenacin was within the M(3) range for five of six and intermediate between M(2) and M(3) for the other specimen tested. The affinity of methoctramine in both organ donor specimens tested was within the M(3) range. Whereas normal detrusor contractions are mediated by the M(3) receptor subtype, in patients with neurogenic bladder dysfunction as well as certain organ transplant donors, contractions can be mediated by the M(2) muscarinic receptor subtype.
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Affiliation(s)
- Michel A Pontari
- Temple University School of Medicine, 3400 N. Broad St., 715 OMS, Philadelphia, PA 19140-5104, USA
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10
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Braverman AS, Ruggieri MR. Hypertrophy changes the muscarinic receptor subtype mediating bladder contraction from M3 toward M2. Am J Physiol Regul Integr Comp Physiol 2003; 285:R701-8. [PMID: 12763741 PMCID: PMC3277086 DOI: 10.1152/ajpregu.00009.2003] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Major pelvic ganglion electrocautery (MPGE) and spinal cord injury in the rat induce bladder hypertrophy and a change in muscarinic receptor subtypes mediating bladder contraction from predominantly M3 to a combination of M2 and M3. To determine whether this is a result of bladder hypertrophy or denervation, we studied the following groups: sham-operated controls, urinary diversion (DIV), MPGE together with urinary diversion (DIV-DEN), bilateral MPGE (DEN), bladder outlet obstruction (BOO), and MPG decentralization (MPGDEC). The degree of bladder denervation was determined by the maximal carbachol response normalized to the response to electric field stimulation. Receptor subtype density was determined by immunoprecipitation. The affinity of subtype-selective muscarinic antagonists for inhibition of carbachol-induced contractions was used to determine the subtype-mediating contraction. DEN, MPG-DEC, and BOO bladders were hypertrophic whereas DIV bladders were atrophic compared with sham operated. Bladder contraction in sham-operated, DIV, and DIV-DEN was mediated by the M3 receptor subtype, whereas the M2 subtype participated in contraction in the DEN, MPG-DEC, and BOO groups. The hypertrophied bladders had an increase in total and M2 receptor density while all experimental groups showed a reduction in M3 receptor density. Thus bladder hypertrophy, independent from bladder denervation, causes a shift in the muscarinic receptor subtype mediating bladder contraction from M3 toward M2.
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Affiliation(s)
- Alan S Braverman
- Temple Univ. School of Medicine, 3400 N. Broad St., 715 OMS, Philadelphia, PA 19140, USA.
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11
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Choppin A. Muscarinic receptors in isolated urinary bladder smooth muscle from different mouse strains. Br J Pharmacol 2002; 137:522-8. [PMID: 12359634 PMCID: PMC1573519 DOI: 10.1038/sj.bjp.0704897] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
1. The pharmacological characteristics of muscarinic receptors in male and female mouse urinary bladder smooth muscle from different strains (C57Bl/6, 129/SvJ and hybrid backcross N1F2) were studied. 2. (+)-Cis-dioxolane, oxotremorine-M, acetylcholine, carbachol and pilocarpine induced concentration-dependent contractions of the urinary bladder smooth muscle (range for pEC(50)=6.4-6.6, 6.2-6.7, 6.2-6.4, 5.4-6.0 and 0.0-5.1, T(max)=1.9-4.7 g, 1.3-3.4 g, 1.0-3.0 g, 1.4-2.4 and 0.0-0.3 g, respectively, n=4-6 depending on the gender and the strain). In females, these contractions were competitively antagonized by a range of muscarinic receptor antagonists (pK(B) value range, depending on the strain): atropine (8.0-8.9), pirenzepine (6.1-6.4), 4-DAMP (7.6-8.4), methoctramine (5.6-6.1), p-F-HHSiD (7.5-7.7), zamifenacin (7.7-8.4) and darifenacin (8.2-8.7). 3. In recontraction studies, in which the muscarinic M(3) receptor population was decreased, and conditions optimized to study M(2) receptor activation, methoctramine exhibited an affinity estimate consistent with muscarinic M(3) receptors (pK(B)=6.26+/-0.08, pA(2)=6.31+/-0.07; pK(B)=6.09+/-0.22, pA(2)=6.08+/-0.01 for female inbred strain 129/SvJ and hybrid backcross N1F2, respectively) or intermediate between the one expected for this compound at M(2) and M(3) receptors, (pK(B)=6.66+/-0.08, pA(2)=7.00+/-0.27 for female inbred strain C57BL/6). 4. These data study suggest that muscarinic M(3) receptors are the predominant, if not the exclusive, subtype mediating contractile responses to muscarinic agonists in female mouse urinary bladder smooth muscle, with strain differences.
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Affiliation(s)
- A Choppin
- Genitourinary-Pharmacology, Deltagen, Inc., Menlo Park, California, CA 94025, USA.
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12
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Braverman AS, Tallarida RJ, Ruggieri MR. Interaction between muscarinic receptor subtype signal transduction pathways mediating bladder contraction. Am J Physiol Regul Integr Comp Physiol 2002; 283:R663-8. [PMID: 12185001 PMCID: PMC3277793 DOI: 10.1152/ajpregu.00116.2002] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
M(3) muscarinic receptors mediate cholinergic-induced contraction in most smooth muscles. However, in the denervated rat bladder, M(2) receptors participate in contraction because M(3)-selective antagonists [para-fluoro-hexahydro-sila-diphenidol (p-F-HHSiD) and 4-DAMP] have low affinities. However, the affinity of the M(2)-selective antagonist methoctramine in the denervated bladder is consistent with M(3) receptor mediating contraction. It is possible that two pathways interact to mediate contraction: one mediated by the M(2) receptor and one by the M(3) receptor. To determine whether an interaction exists, the inhibitory potencies of combinations of methoctramine and p-F-HHSiD for reversing cholinergic contractions were measured. In normal bladders, all combinations gave additive effects. In denervated bladders, synergistic effects were seen with the 10:1 and 1:1 (methoctramine:p-F-HHSiD wt/wt) combinations. After application of the sarcoplasmic reticulum ATPase inhibitor thapsigargin to normal tissue, the 10:1 and 1:1 ratios became synergistic, mimicking denervated tissue. Thus in normal bladders both M(2) and M(3) receptors can induce contraction. In the denervated bladder, the M(2) and the M(3) receptors interact in a facilitatory manner to mediate contraction.
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Affiliation(s)
- Alan S Braverman
- Department of Urology, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, USA
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13
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The Role of M2 Muscarinic Receptor Subtypes Mediating Contraction of the Circular and Longitudinal Smooth Muscle of the Pig Proximal Urethra. J Urol 2002. [DOI: 10.1016/s0022-5347(05)64913-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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14
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The Role of M2 Muscarinic Receptor Subtypes Mediating Contraction of the Circular and Longitudinal Smooth Muscle of the Pig Proximal Urethra. J Urol 2002. [DOI: 10.1097/00005392-200207000-00097] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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15
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Chess-Williams R. Muscarinic receptors of the urinary bladder: detrusor, urothelial and prejunctional. AUTONOMIC & AUTACOID PHARMACOLOGY 2002; 22:133-45. [PMID: 12452898 DOI: 10.1046/j.1474-8673.2002.00258.x] [Citation(s) in RCA: 154] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
1. The parasympathetic nervous system is responsible for maintaining normal bladder function, contracting the bladder smooth muscle (detrusor) and relaxing the bladder outlet during micturition. 2. Contraction of the bladder involves direct contraction via M3 receptors and an indirect 're-contraction' via M2-receptors whereby a reduction in adenylate cyclase activity reverses the relaxation induced by beta-adrenoceptor stimulation. 3. Muscarinic receptors are also located on the epithelial lining of the bladder (urothelium) where they induce the release of a diffusible factor responsible for inhibiting contraction of the underlying detrusor smooth muscle. The factor remains unidentified but is not nitric oxide, a cyclooxygenase product or adenosine triphosphate. 4. Finally, muscarinic receptors are also located prejunctionally in the bladder on cholinergic and adrenergic nerve terminals, where M1-receptors facilitate transmitter release and M2 or M4-receptors inhibit transmitter release. 5. In pathological states, changes may occur in these receptor systems resulting in bladder dysfunction. Muscarinic receptor antagonists are the main therapeutic agents available for treatment of the overactive bladder, but whether their therapeutic effect involves actions at all three locations (detrusor, prejunctional, urothelial) has yet to be established.
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Affiliation(s)
- R Chess-Williams
- Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield, SIO 2TN, UK
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16
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Shen A, Mitchelson F. Characterisation of the prejunctional inhibitory muscarinic receptor on cholinergic nerves in the rat urinary bladder. Eur J Pharmacol 2001; 413:179-87. [PMID: 11226391 DOI: 10.1016/s0014-2999(01)00746-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The nature of the prejunctional inhibitory muscarinic receptor on cholinergic nerve endings in the rat urinary bladder was investigated by measuring stimulated endogenous acetylcholine release via high pressure liquid chromatography (HPLC), in the presence of various selective muscarinic antagonists. The rank order of potencies for the antagonists used was: atropine (-log concentration = 7.8) > 4-DAMP (4-diphenylacetoxy-N-methylpiperidine) (7.6) > tripitramine (7.3) = HHD (hexahydrodifenidol) (7.3) > pFHHSiD (p-fluoro-hexahydrosiladifenidol hydrochloride) (7.0) > himbacine (6.5) > methoctramine (5.9) > or = pirenzepine (5.8) > gallamine (4.3). A comparison of the antagonist potencies obtained, with affinity constants at muscarinic M(1) to M(5) receptors, suggests that the prejunctional inhibitory muscarinic receptor is of the M(4) receptor subtype.
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Affiliation(s)
- A Shen
- Department of Pharmaceutical Biology and Pharmacology, Victorian College of Pharmacy, Monash University, 381 Royal Parade, Parkville, 3052, Victoria, Australia.
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Yamanishi T, Chapple CR, Yasuda K, Chess-Williams R. The role of M(2)-muscarinic receptors in mediating contraction of the pig urinary bladder in vitro. Br J Pharmacol 2000; 131:1482-8. [PMID: 11090124 PMCID: PMC1572475 DOI: 10.1038/sj.bjp.0703719] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
1. In urinary bladder, M(2)-muscarinic receptors predominate, but it is the smaller population of M(3)-receptors which mediate detrusor contraction. This study examines the M(2) : M(3) ratio and the role of M(2)-receptors in contraction of pig urinary bladder. 2. Competition experiments with [(3)H]-QNB determined the ratio of M(2) : M(3). In functional studies, affinity values (pK(B)) for 4-DAMP, darifenacin and methoctramine were calculated. Similar experiments were performed on tissues following selective M(3)-inactivation (incubation with 40 nM 4-DAMP mustard in the presence of 1 microM methoctramine to protect M(2)-receptors), precontraction with 50 mM KCl and relaxation with isoprenaline (30 microM) or forskolin (1 microM). 3. In competition binding, displacement of [(3)H]-QNB by 4-DAMP, darifenacin and methoctramine best fitted a two-site model suggesting a predominant (70 - 80%) population of M(2)-receptors. 4. On normal detrusor in vitro, 4-DAMP and methoctramine caused surmountable antagonism of responses to carbachol with pK(B) values of 9.37+/-0.07 and 6.05+/-0.05 respectively. Darifenacin caused unsurmountable antagonism, the apparent pK(B) value being 8.61+/-0.10. 5. In tissues where the M(3)-receptors had been inactivated and cyclic AMP levels elevated, 4-DAMP and darifenacin were less potent, with apparent pK(B) values of 8.72+/-0.08 and 6.74+/-0.07. In contrast, methoctramine was more potent, the apparent pK(B) value increasing significantly to 6.86+/-0.06. 6. se data suggest that the pig bladder possesses a similar muscarinic receptor population to the human bladder and that the M(3)-receptor subtype mediates contraction of the normal detrusor muscle. However an involvement of M(2)-receptors in contraction can be observed following pharmacological manipulation of the receptor population.
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Affiliation(s)
- Tomonori Yamanishi
- Department of Biomedical Science, University of Sheffield, Sheffield S10 2TN
- Department of Urology, Royal Hallamshire Hospital, Sheffield
| | | | - Kosaku Yasuda
- Department of Urology, Dokkyo University, Koshigaya Hospital, Japan
| | - Russell Chess-Williams
- Department of Biomedical Science, University of Sheffield, Sheffield S10 2TN
- Author for correspondence:
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Abstract
This review focuses on what we consider to be the most important findings of the last year relating to the smooth muscle of the lower urogenital system and the different levels of regulation that control its contraction and relaxation. One level is through modulation of the smooth muscle itself or its environment. Recent findings examining myosin isoform composition and collagen content as well as mechanisms that appear to be involved in inducing hyperplasia/hypertrophy of smooth muscle are described. Another method of regulation is via calcium-dependent phosphorylation of the regulatory light chain of myosin, which increases its activity. Interesting results indicating an uncoupling of force from calcium in the bladder are discussed. A third level of regulation is pharmacologic. Thus, the most recent findings related to receptor subtypes, including muscarinic, endothelin, alpha-adrenergic and nicotinic receptors, are presented. In addition, the effects of diabetes, incontinence, and partial bladder outlet obstruction on these modes of contractile regulation are also discussed.
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Affiliation(s)
- M E DiSanto
- Division of Urology, 3010 Ravdin Courtyard, University of Pennsylvania, 3400 Spruce Street, Philadelphia, PA 19104, USA.
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