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Xu ZH, Jia SK, Chang ZR, Hua YZ, Wang MC, Mei GJ. Facile access to saccharin‐fused 1,4‐dihydropyridines via [3 + 3] annulation reactions. European J Org Chem 2022. [DOI: 10.1002/ejoc.202101423] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Zhi-Hua Xu
- Zhengzhou University College of Chemistry CHINA
| | - Shi-Kun Jia
- Zhengzhou University College of Chemistry CHINA
| | | | | | | | - Guang-Jian Mei
- Zhengzhou University Chemistry Zhengzhou 450001 450001 Zhengzhou CHINA
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Malysz J, Petkov GV. Urinary bladder smooth muscle ion channels: expression, function, and regulation in health and disease. Am J Physiol Renal Physiol 2020; 319:F257-F283. [PMID: 32628539 PMCID: PMC7473901 DOI: 10.1152/ajprenal.00048.2020] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 06/21/2020] [Accepted: 06/28/2020] [Indexed: 12/17/2022] Open
Abstract
Urinary bladder smooth muscle (UBSM), also known as detrusor smooth muscle, forms the bladder wall and ultimately determines the two main attributes of the organ: urine storage and voiding. The two functions are facilitated by UBSM relaxation and contraction, respectively, which depend on UBSM excitability shaped by multiple ion channels. In this review, we summarize the current understanding of key ion channels establishing and regulating UBSM excitability and contractility. They include excitation-enhancing voltage-gated Ca2+ (Cav) and transient receptor potential channels, excitation-reducing K+ channels, and still poorly understood Cl- channels. Dynamic interplay among UBSM ion channels determines the overall level of Cav channel activity. The net Ca2+ influx via Cav channels increases global intracellular Ca2+ concentration, which subsequently triggers UBSM contractility. Here, for each ion channel type, we describe UBSM tissue/cell expression (mRNA and protein) profiles and their role in regulating excitability and contractility of UBSM in various animal species, including the mouse, rat, and guinea pig, and, most importantly, humans. The currently available data reveal certain interspecies differences, which complicate the translational value of published animal research results to humans. This review highlights recent developments, findings on genetic knockout models, pharmacological data, reports on UBSM ion channel dysfunction in animal bladder disease models, and the very limited human studies currently available. Among all gaps in present-day knowledge, the unknowns on expression and functional roles for ion channels determined directly in human UBSM tissues and cells under both normal and disease conditions remain key hurdles in the field.
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Affiliation(s)
- John Malysz
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Georgi V Petkov
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee
- Department of Pharmacology, College of Medicine, University of Tennessee Health Science Center, Memphis, Tennessee
- Department of Urology, College of Medicine, University of Tennessee Health Science Center, Memphis, Tennessee
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Malysz J, Maxwell SE, Yarotskyy V, Petkov GV. TRPM4 channel inhibitors 9-phenanthrol and glibenclamide differentially decrease guinea pig detrusor smooth muscle whole-cell cation currents and phasic contractions. Am J Physiol Cell Physiol 2020; 318:C406-C421. [PMID: 31851526 DOI: 10.1152/ajpcell.00055.2019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Nonselective cation channels, consistent with transient receptor potential melastatin-4 (TRPM4), regulate detrusor smooth muscle (DSM) function. TRPM4 channels can exist as homomers or assemble with sulfonylurea receptors (SURs) as complexes. We evaluated contributions of TRPM4/SUR-TRPM4 channels to DSM excitability and contractility by examining the effects of TRPM4/SUR-TRPM4 channel modulators 9-phenanthrol, glibenclamide, and diazoxide on freshly-isolated guinea pig DSM cells (amphotericin-B perforated patch-clamp electrophysiology) and mucosa-free DSM strips (isometric tension recordings). In DSM cells, complete removal of extracellular Na+ decreased voltage-step-induced cation (non-K+ selective) currents. At high positive membrane potentials, 9-phenanthrol at 100 μM attenuated voltage step-induced currents more effectively than at 30 μM, revealing concentration-dependent, voltage-sensitive inhibition. In comparison to 9-phenanthrol, glibenclamide (100 μM) displayed lower inhibition of cation currents. In the presence of glibenclamide (100 μM), 9-phenanthrol (100 μM) further decreased the currents. The SUR-TRPM4 complex activator diazoxide (100-300 μM) weakly inhibited the currents. 9-Phenanthrol, but not glibenclamide or diazoxide, increased cell capacitance (a cell surface area indicator). In contractility studies, glibenclamide displayed lower potencies than 9-phenanthrol attenuating spontaneous and 20 mM KCl-induced DSM phasic contractions. While both compounds showed similar maximum inhibitions on DSM spontaneous phasic contractions, glibenclamide was generally less efficacious on 20 mM KCl-induced phasic contractions. In summary, the observed differential effects of 9-phenanthrol and glibenclamide on DSM excitability and contractility support unique mechanisms for the two compounds. The data suggest that SUR-TRPM4 complexes do not contribute to DSM function. This study advances our understanding of pharmacological effects of glibenclamide and 9-phenanthrol on DSM cell cation currents.
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Affiliation(s)
- John Malysz
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Sarah E Maxwell
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Viktor Yarotskyy
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Georgi V Petkov
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee
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Gu Z, Wu B, Jiang GF, Zhou YG. Synthesis of Benzofuran-fused 1,4-Dihydropyridines via
Bifunctional Squaramide-catalyzed Formal [4+2] Cycloaddition of Azadienes with Malononitrile. CHINESE J CHEM 2018. [DOI: 10.1002/cjoc.201800330] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Zheng Gu
- College of Chemistry and Chemical Engineering, Hunan University; Changsha Hunan 410082 China
| | - Bo Wu
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences; Dalian Liaoning 116023 China
| | - Guo-Fang Jiang
- College of Chemistry and Chemical Engineering, Hunan University; Changsha Hunan 410082 China
| | - Yong-Gui Zhou
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences; Dalian Liaoning 116023 China
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Yamamoto T, Takahara K, Uchida K, Teramoto N. ZD0947, a sulphonylurea receptor modulator, detects functional sulphonylurea receptor subunits in murine vascular smooth muscle ATP-sensitive K + channels. Eur J Pharmacol 2017; 800:34-39. [PMID: 28213290 DOI: 10.1016/j.ejphar.2017.02.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Revised: 02/13/2017] [Accepted: 02/13/2017] [Indexed: 10/20/2022]
Abstract
In order to identify functional sulphonylurea receptor (SUR.x) subunits of native ATP-sensitive K+ channels (KATP channels) in mouse portal vein, the effects of ZD0947, a SUR.x modulator, were investigated on spontaneous portal vein contractions, macroscopic membrane currents and unitary currents recorded (using patch-clamp techniques) in freshly dispersed mouse portal vein myocytes. Spontaneous contractions in mouse portal vein were reversibly reduced by ZD0947 in a concentration-dependent manner (Ki =293nM). The relaxation elicited by 3µM ZD0947 was antagonized by the additional application of glibenclamide (300nM), but not gliclazide (100-300nM). In the conventional whole-cell configuration, 100µM ZD0947 elicited inward glibenclamide-sensitive currents at a holding potential of -60mV that demonstrated selectivity for K+(i.e. KATP currents). The peak amplitude of the membrane current elicited by 30µM or 100µM ZD0947 was smaller than that elicited by 100µM pinacidil at -60mV. In the cell-attached mode, 100µM ZD0947 activated glibenclamide-sensitive K+ channels with a conductance (35 pS) similar to that of recombinant Kir6.1/SUR2B channels that were expressed in HEK293 cells and activated by 100µM ZD0947. These results demonstrate that ZD0947 caused a significant vascular relaxation through the activation of KATP channels and that SUR2B may be the major functional subunit of SUR.x in mouse portal vein KATP channels, based on its pharmacological selectivity.
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Affiliation(s)
- Tadashi Yamamoto
- Department of Pharmacology, Faculty of Medicine, Saga University, Saga 849-8501, Japan
| | - Kohei Takahara
- Department of Pharmacology, Faculty of Medicine, Saga University, Saga 849-8501, Japan
| | - Keiichiro Uchida
- Department of Pharmacology, Faculty of Medicine, Saga University, Saga 849-8501, Japan
| | - Noriyoshi Teramoto
- Department of Pharmacology, Faculty of Medicine, Saga University, Saga 849-8501, Japan; Laboratory of Biomedical Engineering, Graduate School of Biomedical Engineering, Tohoku University, Sendai 980-8575, Japan.
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Mori K, Yamashita Y, Teramoto N. Effects of ZD0947, a novel and potent ATP-sensitive K + channel opener, on smooth muscle-type ATP-sensitive K + channels. Eur J Pharmacol 2016; 791:773-779. [PMID: 27693800 DOI: 10.1016/j.ejphar.2016.09.038] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Revised: 09/13/2016] [Accepted: 09/28/2016] [Indexed: 10/20/2022]
Abstract
The effects of ZD0947, a novel ATP-sensitive K+ channel (KATP channel) opener, on the activity of reconstituted KATP channels were investigated using cell-attached recordings. KATP channels were studied in HEK 293 cells by co-expression of inwardly rectifying-6 family K+ channel subunits (Kir6.x: Kir6.1 and Kir6.2) with 3 different types of sulphonylurea receptors (SUR.x: SUR1, SUR2A and SUR2B). ZD0947 (100µM) activated SUR2B/Kir6.2 channels in a concentration-dependent manner, but caused only weak activation of SUR1/Kir6.2 channels and SUR2A/Kir6.2 channels expressed in HEK 293 cells. ZD0947 reversibly suppressed diazoxide-elicited SUR1/Kir6.2 channels activity and pinacidil-elicited SUR2A/Kir6.2 channel activity. However, ZD0947 did not affect SUR2B/Kir6.2 channels fully activated by 100µM pinacidil. ZD0947 had little inhibitory effects on the activity of Kir6.2ΔC26 channels (a truncated isoform of Kir6.2) or its mutant channels (i.e. Kir6.2ΔC26C166A) expressed in HEK 293 cells. ZD0947 also elicited activity in SUR2B/Kir6.1 channels expressed in HEK 293 cells, in a concentration-dependent manner. Therefore, ZD0947 is a relatively effective activator of smooth muscle-type KATP channels (SUR2B/Kir6.1 and SUR2B/Kir6.2) but is a partial antagonist of pancreatic-type KATP channels (i.e. SUR1/Kir6.2) and cardiac-type KATP channels (i.e. SUR2A/Kir6.2). These results suggest that a pharmacological agent can possess either agonist or antagonist actions on the activity of KATP channels, depending on the subtype of SUR.x.
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Affiliation(s)
- Keisuke Mori
- Department of Pharmacology, Faculty of Medicine, Saga University, Saga 849-8501, Japan; Department of Oral and Maxillofacial Surgery, Faculty of Medicine, Saga University, Saga 849-8501, Japan
| | - Yoshio Yamashita
- Department of Oral and Maxillofacial Surgery, Faculty of Medicine, Saga University, Saga 849-8501, Japan
| | - Noriyoshi Teramoto
- Department of Pharmacology, Faculty of Medicine, Saga University, Saga 849-8501, Japan; Laboratory of Biomedical Engineering, Graduate School of Biomedical Engineering, Tohoku University, Sendai 980-8575, Japan.
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Shimizu S, Shimizu T, Higashi Y, Saito M. Lower urinary tract symptoms as a vascular dysfunction: the effect of nicorandil as a vasodilator. Nihon Yakurigaku Zasshi 2015; 146:21-6. [PMID: 26165338 DOI: 10.1254/fpj.146.21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Molecular analysis of ATP-sensitive K(+) channel subunits expressed in mouse portal vein. Vascul Pharmacol 2015; 75:29-39. [PMID: 26163942 DOI: 10.1016/j.vph.2015.06.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Revised: 06/16/2015] [Accepted: 06/29/2015] [Indexed: 11/23/2022]
Abstract
BACKGROUND Several combinations of inwardly rectifying K(+) channel 6.x family pore-forming (KIR6.x) subunits associated with sulphonylurea receptor (SUR.x) subunits have been detected among ATP-sensitive K(+) (KATP) channels. It remains to be established which of these is expressed in native vascular smooth muscle. METHODS Pharmacological and electrophysiological properties of KATP channels in mouse portal vein were investigated using tension measurements and patch-clamp techniques. Molecular biological analyses were also performed to investigate the structural properties of these channels. RESULTS Spontaneous contractions in mouse portal vein were reversibly reduced by pinacidil and MCC-134, and the pinacidil-induced relaxation was antagonized by glibenclamide and U-37883A. In cell-attached mode, pinacidil activated glibenclamide-sensitive K(+) channels with a conductance (35 pS) similar to that of KIR6.1. RT-PCR analysis revealed the expression of KIR6.1, KIR6.2 and SUR2B transcripts. Using real-time PCR methods, the quantitative expression of KIR6.1 was much greater than that of KIR6.2. Immunohistochemical studies indicated the presence of KIR6.1 and SUR2B proteins in the smooth muscle layers of mouse portal vein and in single smooth muscle cells dispersed from mouse portal vein. CONCLUSIONS The results indicate that native KATP channels in mouse portal vein are likely to be composed of a heterocomplex of KIR6.1 and SUR2B subunits.
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Iwasa K, Zhu HL, Shibata A, Maehara Y, Teramoto N. Molecular analysis of ATP-sensitive K⁺ channel subunits expressed in mouse vas deferens myocytes. Br J Pharmacol 2014; 171:145-57. [PMID: 24117345 DOI: 10.1111/bph.12437] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Revised: 09/10/2013] [Accepted: 09/13/2013] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND AND PURPOSE ATP-sensitive K(+)(K(ATP)) channels, which are composed of K(IR)6.x associated with sulphonylurea receptor (SUR) subunits, have been detected in native smooth muscle cells, but it is currently not known which of these is expressed in mouse vas deferens myocytes. EXPERIMENTAL APPROACH Pharmacological and electrophysiological properties of K(ATP) channels in mouse vas deferens myocytes were investigated using patch clamp techniques. Molecular biological analyses were performed to examine the properties of these K(ATP) channels. KEY RESULTS During conventional whole-cell recording, pinacidil elicited an inward current that was suppressed by glibenclamide, a sulfonylurea agent, and by U-37883A, a selective K(IR)6.1 blocker. When 0.3 mM ATP was added to the pipette solution, the peak amplitude of the pinacidil-induced current was much smaller than that recorded in its absence. When 3 mM UDP, GDP or ADP was included in the pipette solution, an inward current was elicited after establishment of the conventional whole-cell configuration, with potency order being UDP > GDP > ADP. These nucleoside diphosphate-induced inward currents were suppressed by glibenclamide. MCC-134, a SUR modulator, induced glibenclamide-sensitive K(ATP) currents that were similar to those induced by 100 μM pinacidil. In the cell-attached configuration, pinacidil activated channels with a conductance similar to that of K(IR)6.1. Reverse transcription PCR analysis revealed the expression of K(IR)6.1 and SUR2B transcripts and immunohistochemical studies indicated the presence of K(IR)6.1 and SUR2B proteins in the myocytes. CONCLUSIONS AND IMPLICATIONS Our results indicate that native K(ATP) channels in mouse vas deferens myocytes are a heterocomplex of K(IR)6.1 channels and SUR2B subunits.
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Affiliation(s)
- Kazuomi Iwasa
- Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
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Ekman M, Rippe C, Sadegh MK, Dabestani S, Mörgelin M, Uvelius B, Swärd K. Association of muscarinic M3 receptors and Kir6.1 with caveolae in human detrusor muscle. Eur J Pharmacol 2012; 683:238-45. [DOI: 10.1016/j.ejphar.2012.02.039] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Revised: 02/19/2012] [Accepted: 02/26/2012] [Indexed: 01/04/2023]
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Saito M, Ohmasa F, Tsounapi P, Inoue S, Dimitriadis F, Kinoshita Y, Satoh K. Nicorandil ameliorates hypertension-related bladder dysfunction in the rat. Neurourol Urodyn 2012; 31:695-701. [DOI: 10.1002/nau.21213] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Accepted: 08/01/2011] [Indexed: 11/09/2022]
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Ohmasa F, Saito M, Oiwa H, Tsounapi P, Shomori K, Kitatani K, Dimitriadis F, Kinoshita Y, Satoh K. Pharmacological preconditioning of ATP-sensitive potassium channel openers on acute urinary retention-induced bladder dysfunction in the rat. BJU Int 2012; 110:E245-52. [DOI: 10.1111/j.1464-410x.2012.10965.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Diphosphate regulation of adenosine triphosphate sensitive potassium channel in human bladder smooth muscle cells. J Urol 2011; 186:736-44. [PMID: 21683406 DOI: 10.1016/j.juro.2011.03.153] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2010] [Indexed: 11/21/2022]
Abstract
PURPOSE To clarify the properties of adenosine triphosphate sensitive K+ channel in human detrusor smooth muscle we examined the effect of the representative nicotinic acid derivatives β-nicotinamide adenine dinucleotide, cyclic adenosine diphosphate ribose and nicotinic acid adenine dinucleotide phosphate (Sigma-Aldrich®) on human detrusor adenosine triphosphate sensitive K+ channels. MATERIALS AND METHODS Patch clamp procedures were done in human detrusor cells. Reverse transcriptase and real-time polymerase chain reaction were performed to clarify the subunit components of adenosine triphosphate sensitive K+ channels. RESULTS The K+ channel opener levcromakalim induced a long lasting outward current that was inhibited by glibenclamide (Sigma-Aldrich) under the whole cell configuration. The single channel study revealed that the unitary conductance of the adenosine triphosphate sensitive K+ channel in the human detrusor was 11 pS and nucleotide diphosphates increased its open probability. Applying β-nicotinamide adenine dinucleotide also activated the adenosine triphosphate sensitive K+ channel but applying cyclic adenosine diphosphate ribose or nicotinic acid adenine dinucleotide phosphate had little effect on channel activation. Molecular studies indicated that Kir6.1 and SUR2B were the predominant components of the adenosine triphosphate sensitive K+ channel in the human detrusor. CONCLUSIONS To our knowledge we report the first single channel study of the adenosine triphosphate sensitive K+ channel in the human detrusor. The properties of this channel, ie unitary conductance, adenosine triphosphate sensitivity and diphosphate activation, were consistent with those of other smooth muscle organs. β-Nicotinamide adenine dinucleotide has the potency to activate adenosine triphosphate sensitive K+ channels in the human detrusor. This channel likely has some role during ischemic conditions as well as physiological muscle motion leading to the activation of cell metabolism.
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Kajioka S, Nakayama S, Asano H, Seki N, Naito S, Brading AF. Levcromakalim and MgGDP activate small conductance ATP-sensitive K+ channels of K+ channel pore 6.1/sulfonylurea receptor 2A in pig detrusor smooth muscle cells: uncoupling of cAMP signal pathways. J Pharmacol Exp Ther 2008; 327:114-23. [PMID: 18596222 DOI: 10.1124/jpet.108.140269] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Pharmacological studies have suggested the existence of ATP-sensitive K(+) (K(ATP)) channel as a therapeutic target in urinary bladders; however, electrical properties have not yet been shown. Patch-clamp techniques were applied to investigate the properties of K(ATP) channels in pig detrusor cells. In whole-cell configuration, levcromakalim, a K(ATP) channel opener, induced a long-lasting outward current in a concentration-dependent manner. The current-voltage curve of the levcromakalim-induced membrane current intersected at approximately -80 mV. This current was abolished by glibenclamide. Intracellular application of 0.1 mM GDP significantly enhanced the levcromakalim-induced membrane current, whereas cAMP did not. Furthermore, neurotransmitters related to cAMP signaling, such as calcitonin gene-related peptide, vasointestinal peptide, adenosine, and somatostatin, had little effect on the membrane current. In cell-attached configuration, levcromakalim activated K(+) channels with a unitary conductance of approximately 12 pS. When the patch configuration was changed to inside-out mode, the K(+) channel activity ran down. Subsequent application of 1 mM GDP reactivated the channels. The openings of the approximately 12 pS K(+) channels in the presence of 1 mM GDP was suppressed by ATP and glibenclamide. In reverse transcription-polymerase chain reaction, K(+) channel pore 6.1 and sulfonylurea receptor (SUR)2A were predominant in pig detrusor cells. The 12 pS K(+) channel activated by levcromakalim in pig detrusor smooth muscle cells is a K(ATP) channel. The predominant expression of SUR2A can account for the lack of effect of neurotransmitters related to cAMP.
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Comparative studies of ZD0947, a novel ATP-sensitive K(+) channel opener, on guinea pig detrusor and aortic smooth muscles. Naunyn Schmiedebergs Arch Pharmacol 2007; 376:309-19. [PMID: 18071674 DOI: 10.1007/s00210-007-0241-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2007] [Accepted: 11/26/2007] [Indexed: 12/24/2022]
Abstract
The effects of ZD0947, a novel urinary bladder selective ATP-sensitive potassium channel (K(ATP) channel) opener, on carbachol-induced contractions of isolated guinea pig urinary bladder strips were investigated to compare its ability to relax norepinephrine-induced contraction of the aorta. Electrophysiological techniques were also utilized to compare the effects of ZD0947 on membrane currents between guinea pig detrusor and aortic myocytes. ZD0947 caused a significant reduction of the carbachol-induced contractile activity, demonstrating a biphasic relaxation (the first and second components). Although glibenclamide antagonized the effects of two components for the ZD0947-induced relaxation, gliclazide, a selective sulphonylurea receptor 1 (SUR1) antagonist, reduced the effects of the first component but not the second component of the ZD0947-induced relaxation. ZD0947 also reduced the norepinephrine-induced contraction of the aorta. ZD0947 reduced electrical excitability of detrusor smooth muscles, inhibiting spike discharges and also hyperpolarizing the membrane as measured with microelectrodes. In conventional whole-cell configuration, ZD0947 caused a glibenclamide-sensitive K(+) current (i.e., K(ATP) current) at a holding potential of -60 mV in guinea pig detrusor and aortic myocytes. The current density of ZD0947-induced K(ATP) currents in guinea pig detrusor myocytes was significantly larger than that in aortic smooth muscle cells. These results show that ZD0947 caused a significant relaxation through the activation of K(ATP) channels in detrusor muscle.
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Signal transduction underlying the control of urinary bladder smooth muscle tone by muscarinic receptors and beta-adrenoceptors. Naunyn Schmiedebergs Arch Pharmacol 2007; 377:449-62. [PMID: 18060543 PMCID: PMC2480512 DOI: 10.1007/s00210-007-0208-0] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2007] [Accepted: 10/21/2007] [Indexed: 12/17/2022]
Abstract
The normal physiological contraction of the urinary bladder, which is required for voiding, is predominantly mediated by muscarinic receptors, primarily the M3 subtype, with the M2 subtype providing a secondary backup role. Bladder relaxation, which is required for urine storage, is mediated by β-adrenoceptors, in most species involving a strong β3-component. An excessive stimulation of contraction or a reduced relaxation of the detrusor smooth muscle during the storage phase of the micturition cycle may contribute to bladder dysfunction known as the overactive bladder. Therefore, interference with the signal transduction of these receptors may be a viable approach to develop drugs for the treatment of overactive bladder. The prototypical signaling pathway of M3 receptors is activation of phospholipase C (PLC), and this pathway is also activated in the bladder. Nevertheless, PLC apparently contributes only in a very minor way to bladder contraction. Rather, muscarinic-receptor-mediated bladder contraction involves voltage-operated Ca2+ channels and Rho kinase. The prototypical signaling pathway of β-adrenoceptors is an activation of adenylyl cyclase with the subsequent formation of cAMP. Nevertheless, cAMP apparently contributes in a minor way only to β-adrenoceptor-mediated bladder relaxation. BKCa channels may play a greater role in β-adrenoceptor-mediated bladder relaxation. We conclude that apart from muscarinic receptor antagonists and β-adrenoceptor agonists, inhibitors of Rho kinase and activators of BKCa channels may have potential to treat an overactive bladder.
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Yoshimura N, Kaiho Y, Miyazato M, Yunoki T, Tai C, Chancellor MB, Tyagi P. Therapeutic receptor targets for lower urinary tract dysfunction. Naunyn Schmiedebergs Arch Pharmacol 2007; 377:437-48. [PMID: 18034230 DOI: 10.1007/s00210-007-0209-z] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2007] [Accepted: 10/22/2007] [Indexed: 01/25/2023]
Abstract
The functions of the lower urinary tract, to store and periodically release urine, are dependent on the activity of smooth and striated muscles in the bladder, urethra, and external urethral sphincter. During urine storage, the outlet is closed, and the bladder smooth muscle is quiescent. When bladder volume reaches the micturition threshold, activation of a micturition center in the dorsolateral pons (the pontine micturition center) induces a bladder contraction and a reciprocal relaxation of the urethra, leading to bladder emptying. During voiding, sacral parasympathetic (pelvic) nerves provide an excitatory input (cholinergic and purinergic) to the bladder and inhibitory input (nitrergic) to the urethra. These peripheral systems are integrated by excitatory and inhibitory regulation at the levels of the spinal cord and the brain. Injury or diseases of the nervous system, as well as drugs and disorders of the peripheral organs, can produce lower urinary tract dysfunction. In the overactive bladder (OAB) condition, therapeutic targets for facilitation of urine storage can be found at the levels of the urothelium, detrusor muscles, autonomic and afferent pathways, spinal cord, and brain. There is increasing evidence showing that the urothelium has specialized sensory and signaling properties including: (1) expression of nicotinic, muscarinic, tachykinin, adrenergic, bradykinin, and transient receptor potential (TRP) receptors, (2) close physical association with afferent nerves, and (3) ability to release chemical molecules such as adenosine triphosphate (ATP), acetylcholine, and nitric oxide. Increased expression and/or sensitivity of these urothelial-sensory molecules that lead to afferent sensitization have been documented as possible pathogenesis of OAB. Targeting afferent pathways and/or bladder smooth muscles by modulating activity of ligand receptors (e.g., neurokinin, ATP, or beta3-adrenergic receptors) and ion channels (e.g., TRPV1 or K) could be effective to suppress OAB. In the stress urinary incontinence condition, pharmacotherapies targeting the neurally mediated urethral continence reflex during stress conditions such as sneezing or coughing could be effective for increasing the outlet resistance. Therapeutic targets include adrenergic and serotonergic receptors in the spinal cord as well as adrenergic receptors at the urethral sphincter, which can enhance urethral reflex activity during stress conditions and increase baseline urethral pressure, respectively.
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Affiliation(s)
- Naoki Yoshimura
- Department of Urology, University of Pittsburgh School of Medicine, Suite 700 Kaufmann Medical Building, 3471 Fifth Avenue, Pittsburgh, PA 15213, USA.
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Abstract
PURPOSE OF REVIEW The overactive bladder is a common and distressing condition that has a significant impact on the quality of life of many people worldwide. Anticholinergics remain the first line in pharmacotherapy, however the use of these agents is hindered by adverse effects and limited efficacy. Thus there is a need for more effective treatments. Recently, there has been a move towards targeting novel pathways thought to play a role in overactivity. This review aims to provide an insight into the recent developments in pharmacotherapy of the overactive bladder. RECENT FINDINGS With recent advances in our understanding of the basic science of the overactive bladder it is becoming clear that the control of bladder functioning is far more complex than previously believed. Peripherally, a prominent role has emerged for the urothelium and the underlying suburothelium in mechanosensory control, and the role of afferent pathways in pathophysiology is increasingly recognized. SUMMARY Recent research has highlighted several potential targets for treatment of the overactive bladder, particularly within the mechanosensory pathways. With the exception of botulinum toxin, however, few new therapies have emerged showing clinical benefits. A clearer understanding of the pathophysiology of the bladder will hopefully lead to more effective and tolerated treatments.
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Affiliation(s)
- Donna J Sellers
- Biomedical Research Centre, Sheffield Hallam University, Sheffield, UK.
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Bibliography. Current world literature. Female urology. Curr Opin Urol 2007; 17:287-90. [PMID: 17558274 DOI: 10.1097/mou.0b013e3281fbd54d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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