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Abstract
Phospholipase C (PLC) family members constitute a family of diverse enzymes. Thirteen different family members have been cloned. These family members have unique structures that mediate various functions. Although PLC family members all appear to signal through the bi-products of cleaving phospholipids, it is clear that each family member, and at times each isoform, contributes to unique cellular functions. This chapter provides a review of the current literature on PLC. In addition, references have been provided for more in-depth information regarding areas that are not discussed including tyrosine kinase activation of PLC. Understanding the roles of the individual PLC enzymes, and their distinct cellular functions, will lead to a better understanding of the physiological roles of these enzymes in the development of diseases and the maintenance of homeostasis.
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Dér B, Molnár PJ, Ruisanchez É, Őrsy P, Kerék M, Faragó B, Nyirády P, Offermanns S, Benyó Z. NK2 receptor-mediated detrusor muscle contraction involves G q/11-dependent activation of voltage-dependent Ca 2+ channels and the RhoA-Rho kinase pathway. Am J Physiol Renal Physiol 2019; 317:F1154-F1163. [PMID: 31461351 DOI: 10.1152/ajprenal.00106.2019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Tachykinins (TKs) are involved in both the physiological regulation of urinary bladder functions and development of overactive bladder syndrome. The aim of the present study was to investigate the signal transduction pathways of TKs in the detrusor muscle to provide potential pharmacological targets for the treatment of bladder dysfunctions related to enhanced TK production. Contraction force, intracellular Ca2+ concentration, and RhoA activity were measured in the mouse urinary bladder smooth muscle (UBSM). TKs and the NK2 receptor (NK2R)-specific agonist [β-Ala8]-NKA(4-10) evoked contraction, which was inhibited by the NKR2 antagonist MEN10376. In Gαq/11-deficient mice, [β-Ala8]-NKA(4-10)-induced contraction and the intracellular Ca2+ concentration increase were abolished. Although Gq/11 proteins are linked principally to phospholipase Cβ and inositol trisphosphate-mediated Ca2+ release from intracellular stores, we found that phospholipase Cβ inhibition and sarcoplasmic reticulum Ca2+ depletion failed to have any effect on contraction induced by [β-Ala8]-NKA(4-10). In contrast, lack of extracellular Ca2+ or blockade of voltage-dependent Ca2+ channels (VDCCs) suppressed contraction. Furthermore, [β-Ala8]-NKA(4-10) increased RhoA activity in the UBSM in a Gq/11-dependent manner and inhibition of Rho kinase with Y-27632 decreased contraction force, whereas the combination of Y-27632 with either VDCC blockade or depletion of extracellular Ca2+ resulted in complete inhibition of [β-Ala8]-NKA(4-10)-induced contractions. In summary, our results indicate that NK2Rs are linked exclusively to Gq/11 proteins in the UBSM and that the intracellular signaling involves the simultaneous activation of VDCC and the RhoA-Rho kinase pathway. These findings may help to identify potential therapeutic targets of bladder dysfunctions related to upregulation of TKs.
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Affiliation(s)
- Bálint Dér
- Institute of Translational Medicine, Semmelweis University, Budapest, Hungary
| | - Péter József Molnár
- Institute of Translational Medicine, Semmelweis University, Budapest, Hungary.,Department of Urology, Semmelweis University, Budapest, Hungary
| | - Éva Ruisanchez
- Institute of Translational Medicine, Semmelweis University, Budapest, Hungary
| | - Petra Őrsy
- Institute of Translational Medicine, Semmelweis University, Budapest, Hungary
| | - Margit Kerék
- Institute of Translational Medicine, Semmelweis University, Budapest, Hungary
| | - Bernadett Faragó
- Institute of Translational Medicine, Semmelweis University, Budapest, Hungary
| | - Péter Nyirády
- Department of Urology, Semmelweis University, Budapest, Hungary
| | - Stefan Offermanns
- Department of Pharmacology, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Zoltán Benyó
- Institute of Translational Medicine, Semmelweis University, Budapest, Hungary
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Muscarinic receptor-induced contractions of the detrusor are impaired in TRPC4 deficient mice. Sci Rep 2018; 8:9264. [PMID: 29915209 PMCID: PMC6006323 DOI: 10.1038/s41598-018-27617-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Accepted: 06/06/2018] [Indexed: 01/25/2023] Open
Abstract
Acetylcholine contracts the bladder by binding to muscarinic M3 receptors on the detrusor, leading to Ca2+ influx via voltage-gated Ca2+ channels. The cellular mechanisms linking these events are poorly understood, but studies have suggested that activation of TRPC4 channels could be involved. The purpose of this study was to investigate if spontaneous and cholinergic-mediated contractions of the detrusor were impaired in TRPC4 deficient (TRPC4−/−) mice. Isometric tension recordings were made from strips of wild-type (WT) and TRPC4−/− detrusor. Spontaneous phasic detrusor contractions were significantly smaller in TRPC4−/− mice compared to wild-type, however no difference in response to exogenous application of 60 mM KCl was observed. Cholinergic responses, induced by electric-field stimulation (EFS), bath application of the cholinergic agonist carbachol, or the acetylcholinesterase inhibitor neostigmine were all significantly smaller in TRPC4−/− detrusor strips than wild-type. Surprisingly, the TRPC4/5 inhibitor ML204 reduced EFS and CCh-evoked contractions in TRPC4−/− detrusor strips. However, TRPC5 expression was up-regulated in these preparations and, in contrast to wild-type, EFS responses were reduced in amplitude by the TRPC5 channel inhibitor clemizole hydrochloride. This study demonstrates that TRPC4 channels are involved in spontaneous and cholinergic-mediated contractions of the murine detrusor. TRPC5 expression is up-regulated in TRPC4−/− detrusor strips, and may partially compensate for loss of TRPC4 channels.
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Griffin CS, Bradley E, Hollywood MA, McHale NG, Thornbury KD, Sergeant GP. β3-adrenoceptor agonists inhibit carbachol-evoked Ca 2+ oscillations in murine detrusor myocytes. BJU Int 2018; 121:959-970. [PMID: 29211339 DOI: 10.1111/bju.14090] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
OBJECTIVE To test if carbachol (CCh)-evoked Ca2+ oscillations in freshly isolated murine detrusor myocytes are affected by β3-adrenoceptor (β-AR) modulators. MATERIALS AND METHODS Isometric tension recordings were made from strips of murine detrusor, and intracellular Ca2+ measurements were made from isolated detrusor myocytes using confocal microscopy. Transcriptional expression of β-AR sub-types in detrusor strips and isolated detrusor myocytes was assessed using reverse transcriptase-polymerase chain reaction (RT-PCR) and real-time quantitative PCR (qPCR). Immunocytochemistry experiments, using a β3-AR selective antibody, were performed to confirm that β3-ARs were present on detrusor myocytes. RESULTS The RT-PCR and qPCR experiments showed that β1-, β2- and β3-AR were expressed in murine detrusor, but that β3-ARs were the most abundant sub-type. The selective β3-AR agonist BRL37344 reduced the amplitude of CCh-induced contractions of detrusor smooth muscle. These responses were unaffected by addition of the BK channel blocker iberiotoxin. BRL37344 also reduced the amplitude of CCh-induced Ca2+ oscillations in freshly isolated murine detrusor myocytes. This effect was mimicked by CL316,243, another β3-AR agonist, and inhibited by the β3-AR antagonist L748,337, but not by propranolol, an antagonist of β1- and β2-ARs. BRL37344 did not affect caffeine-evoked Ca2+ transients or L-type Ca2+ current in isolated detrusor myocytes. CONCLUSION Inhibition of cholinergic-mediated contractions of the detrusor by β3-AR agonists was associated with a reduction in Ca2+ oscillations in detrusor myocytes.
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Affiliation(s)
- Caoimhin S Griffin
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Co Louth, Ireland
| | - Eamonn Bradley
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Co Louth, Ireland
| | - Mark A Hollywood
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Co Louth, Ireland
| | - Noel G McHale
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Co Louth, Ireland
| | - Keith D Thornbury
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Co Louth, Ireland
| | - Gerard P Sergeant
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Co Louth, Ireland
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Griffin CS, Bradley E, Dudem S, Hollywood MA, McHale NG, Thornbury KD, Sergeant GP. Muscarinic Receptor Induced Contractions of the Detrusor are Mediated by Activation of TRPC4 Channels. J Urol 2016; 196:1796-1808. [PMID: 27287524 DOI: 10.1016/j.juro.2016.05.108] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/28/2016] [Indexed: 11/27/2022]
Abstract
PURPOSE Muscarinic receptor mediated contractions of the detrusor rely on Ca2+ influx through voltage-gated Ca2+ channels but to our knowledge the mechanism linking stimulation of M3Rs to the activation of voltage dependent Ca2+ channels has not been established. TRPC4 channels are receptor operated cation channels that couple muscarinic receptor activation to depolarization of intestinal smooth muscle cells, voltage-activated Ca2+ influx and contraction. We investigated whether TRPC4 channels are involved in cholinergic mediated contractions of the detrusor. MATERIALS AND METHODS Isometric tension recordings were made on strips of murine detrusor and intracellular Ca2+ measurements were made on isolated detrusor myocytes using confocal microscopy. Transcriptional expression of TRPC and IP3R subtypes in intact detrusor strips and isolated detrusor myocytes was assessed using reverse transcriptase-polymerase chain reaction. RESULTS Cholinergic stimulation of the detrusor induced by electrical field stimulation or exogenous application of carbachol or neostigmine evoked contractions consisting of a transient plus a tonic response, which was blocked by ML204, an inhibitor of TRPC4 channels. A phasic oscillatory component was blocked by the IP3R inhibitor 2-APB. Carbachol evoked reproducible Ca2+ responses in isolated detrusor myocytes, consisting of an initial Ca2+ transient followed by Ca2+ oscillations. ML204 inhibited the initial Ca2+ transient whereas 2-APB inhibited the Ca2+ oscillations. Reverse transcriptase-polymerase chain reaction experiments showed that TRPC4β, TRPC6 and IP3R1 were selectively expressed in isolated detrusor myocytes. Control experiments demonstrated that ML204 did not affect L-type Ca2+ or BK current amplitude, caffeine induced Ca2+ transients or KCl induced contractions of the detrusor. CONCLUSIONS Muscarinic receptor mediated contractions of the detrusor involve the activation of TRPC4β channels.
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Affiliation(s)
- Caoimhin S Griffin
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Ireland
| | - Eamonn Bradley
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Ireland
| | - Srikanth Dudem
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Ireland
| | - Mark A Hollywood
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Ireland
| | - Noel G McHale
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Ireland
| | - Keith D Thornbury
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Ireland
| | - Gerard P Sergeant
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Ireland.
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Tsai MH, Kamm KE, Stull JT. Signalling to contractile proteins by muscarinic and purinergic pathways in neurally stimulated bladder smooth muscle. J Physiol 2012; 590:5107-21. [PMID: 22890701 DOI: 10.1113/jphysiol.2012.235424] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Urinary bladder smooth muscle contraction is triggered by parasympathetic nerves, which release ATP and acetylcholine (ACh) that bind to purinergic and muscarinic receptors, respectively. Neuronal signalling may thus elicit myosin regulatory light chain (RLC) phosphorylation and contraction through the combined, but distinct contributions of these receptors. Both receptors mediate Ca2+ influx whereas muscarinic receptors may also recruit Ca2+-sensitization mechanisms. Using transgenic mice expressing calmodulin sensor myosin light chain kinase (MLCK) in smooth muscles, the effects of suramin/α,β-methylene ATP (α,β-meATP) (purinergic inhibition) or atropine (muscarinic inhibition) on neurally stimulated elevation of [Ca2+]i, MLCK activation, force and phosphorylation of RLC, myosin light chain phosphatase (MLCP) targeting subunit MYPT1 and MLCP inhibitor protein CPI-17 were examined. Electric field stimulation (EFS) increased [Ca2+]i, MLCK activation and concomitant force in a frequency-dependent manner. The dependence of force on [Ca2+]i and MLCK activation decreased with time suggesting increased Ca2+ sensitization in the late contractile phase. RLC and CPI-17 phosphorylation increased upon stimulation with maximal responses at 20 Hz; both responses were attenuated by atropine, but only RLC phosphorylation was inhibited by suramin/α,β-meATP. Antagonism of purinergic receptors suppressed maximal MLCK activation to a greater extent in the early contractile phase than in the late contractile phase; atropine had the opposite effect. A frequency- and time-dependent increase in MLCK phosphorylation explained the desensitization of MLCK to Ca2+, since MLCK activation declined more rapidly than [Ca2+]i. EFS elicited little or no effect on MYPT1 Thr696 or 850 phosphorylation. Thus, purinergic Ca2+ signals provide the initial activation of MLCK with muscarinic receptors supporting sustained responses. Activation of muscarinic receptors recruits CPI-17, but not MYPT1-mediated Ca2+ sensitization. Furthermore, nerve-released ACh also initiates signalling cascades leading to phosphorylation-dependent desensitization of MLCK.
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Affiliation(s)
- Ming-Ho Tsai
- Department of Physiology, UT Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390-9040, USA
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Abstract
Phospholipase C (PLC) family members constitute a family of diverse enzymes. Thirteen different family members have been cloned. These family members have unique structures that mediate diverse functions. Although PLC family members all appear to signal through the bi-products of cleaving phospholipids, it is clear that each family member, and at times each isoform, contributes to unique cellular functions. This chapter provides a review of the current literature. In addition, references have been provided for more in depth information regarding areas that are discussed. Ultimately, understanding the roles of the individual PLC enzymes, and their distinct cellular functions, will lead to a better understanding of the development of diseases and the maintenance of homeostasis.
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Macmillan D, McCarron JG. The phospholipase C inhibitor U-73122 inhibits Ca(2+) release from the intracellular sarcoplasmic reticulum Ca(2+) store by inhibiting Ca(2+) pumps in smooth muscle. Br J Pharmacol 2010; 160:1295-301. [PMID: 20590621 DOI: 10.1111/j.1476-5381.2010.00771.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND AND PURPOSE The sarcoplasmic reticulum (SR) releases Ca(2+) via inositol 1,4,5-trisphosphate receptors (IP(3)R) in response to IP(3)-generating agonists. Ca(2+) release subsequently propagates as Ca(2+) waves. To clarify the role of IP(3) production in wave generation, the contribution of a key enzyme in the production of IP(3) was examined using a phosphoinositide-specific phospholipase C (PI-PLC) inhibitor, U-73122. EXPERIMENTAL APPROACH Single colonic myocytes were voltage-clamped in whole-cell configuration and cytosolic Ca(2+) concentration ([Ca(2+)](cyto)) measured using fluo-3. SR Ca(2+) release was evoked either by activation of IP(3)Rs (by carbachol or photolysis of caged IP(3)) or ryanodine receptors (RyRs; by caffeine). KEY RESULTS U-73122 inhibited carbachol-evoked [Ca(2+)](cyto) transients. The drug also inhibited [Ca(2+)](cyto) increases, evoked by direct IP(3)R activation (by photolysis of caged IP(3)) and RyR activation (by caffeine), which do not require PI-PLC activation. U-73122 also increased steady-state [Ca(2+)](cyto) and slowed the rate of Ca(2+) removal from the cytoplasm. An inactive analogue of U-73122, U-73343, was without effect on either IP(3)R- or RyR-mediated Ca(2+) release. CONCLUSIONS AND IMPLICATIONS U-73122 inhibited carbachol-evoked [Ca(2+)](cyto) increases. However, the drug also reduced Ca(2+) release when evoked by direct activation of IP(3)R or RyR, slowed Ca(2+) removal and increased steady-state [Ca(2+)](cyto). These results suggest U-73122 reduces IP(3)-evoked Ca(2+) transients by inhibiting the SR Ca(2+) pump to deplete the SR of Ca(2+) rather than by inhibiting PI-PLC.
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Affiliation(s)
- D Macmillan
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK.
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Huster M, Frei E, Hofmann F, Wegener JW. A complex of Ca(V)1.2/PKC is involved in muscarinic signaling in smooth muscle. FASEB J 2010; 24:2651-9. [PMID: 20371628 DOI: 10.1096/fj.09-149856] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Here we present functional and biochemical evidence for a Ca(2+) channel (Ca(V)1.2)/protein kinase C (PKC) signaling complex being a key player in muscarinic regulation of urinary bladder smooth muscle. Muscarinic stimulation induced Ca(2+) signals and concomitant contractions in detrusor muscle from mice that were dependent on functional Ca(2+) channels. These signals were still present in muscles being depolarized by 85 mM extracellular K(+). Muscarinic-induced contractions were reduced by a PKC inhibitor [bisindolylmaleimide I (BIM-I)] and a phospholipase D (PLD) inhibitor (1-butanol). A phorbol ester (PDBu) enlarged muscarinic-induced Ca(2+) signals and contractions. The effects of BIM-I and PDBu were inhibited by isradipine and/or absent in muscles from Ca(V)1.2-deficient mice. Both carbachol and PDBu increased Ca(V)1.2 channel currents in isolated bladder myocytes. Blue native-PAGE electrophoresis revealed that Ca(V)1.2, PKC, and PLD are closely associated in muscles being previously stimulated by carbachol. Immunoprecipitation using anti-Ca(V)1.2 followed by Western blotting demonstrated that Ca(V)1.2 and PKC are coupled in stimulated muscles from wild-type mice. Autoradiography on immunoprecipitates showed that Ca(V)1.2 is a substrate for PKC-mediated phosphorylation. These findings suggest that a signaling complex consisting of Ca(V)1.2, PKC, and, probably, PLD controls muscarinic-mediated phasic contraction of urinary bladder smooth muscle.
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Affiliation(s)
- Maria Huster
- Institut für Pharmakologie und Toxikologie, TU München, Biedersteiner Str. 29, 80802 Munich, Germany
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Propping S, Braeter M, Grimm MO, Wirth MP, Ravens U, Wuest M. Anticholinergic effects of cis- and trans-isomers of two metabolites of propiverine. Naunyn Schmiedebergs Arch Pharmacol 2010; 381:329-38. [PMID: 20182702 DOI: 10.1007/s00210-010-0493-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2009] [Accepted: 01/26/2010] [Indexed: 10/19/2022]
Abstract
The muscarinic receptor antagonist propiverine used for therapy of overactive bladder undergoes first pass metabolism, leading to several active metabolites, which affect muscarinic receptors and L-type Ca(2+) channels with different potencies. M-5, the major metabolite in blood, and M-6 can be synthesized as cis- and trans-isomers. We systematically investigated the pharmacodynamic profiles of the isomers on detrusor contractile function. In murine and porcine detrusor, the effects of the derivatives were examined on contractions induced by electric field stimulation (EFS), cumulatively increasing concentrations of carbachol or high KCl concentration. EFS contractions were concentration-dependently reduced by the M-5 and M-6 isomers although to a different extent. M-5(cis) was slightly more potent than M-5(trans), but the differences did not reach statistical significance. M-6(cis) was significantly more potent than M-6(trans). Responses to carbachol were antagonized by all compounds due to rightward shifts of the concentration-response curves, but only M-5(trans) also significantly reduced the maximum response. pK (B) values obtained with Schild plot analysis indicated slightly higher potency for M-6(cis) than M-6(trans). Ca(2+) influx-dependent contractions elicited by K(+) depolarization were less impaired by low concentrations of the M-6 isomers, but strongly suppressed by 100 microM of the M-5 isomers, suggesting an additional effect of the two M-5 isomers on Ca(2+) influx. All investigated isomers of M-5 and M-6 are biologically active in reducing detrusor contraction in animal tissue. While M-5( cis,) M-6(cis), and M-6(trans) possess surmountable or partially surmountable antagonistic properties at muscarinic receptors, M-5(trans) is a strong non-competitive antagonist. However, at higher concentration ranges, all four compounds seem to have additional effects on Ca(2+) influx.
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Affiliation(s)
- Stefan Propping
- Department of Urology, University Hospital Carl Gustav Carus, Dresden University of Technology, Fetscherstrasse 74, 01307 Dresden, Germany.
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Basha M, Labelle EF, Northington GM, Wang T, Wein AJ, Chacko S. Functional significance of muscarinic receptor expression within the proximal and distal rat vagina. Am J Physiol Regul Integr Comp Physiol 2009; 297:R1486-93. [PMID: 19741053 DOI: 10.1152/ajpregu.90516.2008] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Information regarding the role of cholinergic nerves in mediating vaginal smooth muscle contraction is sparse, and in vitro studies of the effects of muscarinic agonists on vaginal smooth muscle are discrepant. The goal of this study was to determine the expression of muscarinic receptors in the vaginal wall of the rat. In addition, we sought to determine the effect of the muscarinic receptor agonist carbachol on contractility and inositol phosphate production of the proximal and distal rat vaginal muscularis. RT-PCR analysis indicated that both M(2) and M(3) receptor transcripts were expressed within the proximal and distal rat vagina. Carbachol dose-dependently (10(-7)-10(-4) M) contracted the rat vaginal muscularis with a greater maximal contractile response in the proximal vagina (P < 0.01) compared with the distal vagina. The contractile responses of the rat vaginal muscularis to carbachol were dose dependently inhibited by the M(3) antagonist para-fluoro-hexahydrosiladefenidol, and a pK(B) of 7.78 and 7.95 was calculated for the proximal and distal vagina, respectively. Inositol phosphate production was significantly increased in both regions of the vagina following 20-min exposure to 50 muM carbachol with higher levels detected in the proximal vagina compared with the distal (P < 0.05). Preliminary experiments indicated the presence of M(2) and M(3) receptors in the human vaginal muscularis as well as contraction of human vaginal muscularis to carbachol, indicating that our animal studies are relevant to human tissue. Our results provide strong evidence for the functional significance of M(3) receptor expression in the vaginal muscularis.
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Affiliation(s)
- Maureen Basha
- Department of Pharmacology and Physiology, Drexel University College of Medicine; Philadelphia, USA
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