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West EG, McDermott C, Chess-Williams R, Sellers DJ. Partial recovery of voiding function in female mice following repeated psychological stress exposure. PLoS One 2022; 17:e0266458. [PMID: 35446874 PMCID: PMC9022836 DOI: 10.1371/journal.pone.0266458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 03/22/2022] [Indexed: 11/26/2022] Open
Abstract
Psychological stress causes bladder dysfunction in humans and in rodent models, with increased urinary frequency and altered contractile responses evident following repeated environmental stress exposure. However, whether these changes persist after removal of the stressor is unknown, and the aim of this study was to determine if stress-induced changes in voiding behaviour and bladder function recover following removal of the stressor. Adult female mice were allocated to three groups: Unstressed, Stressed or Stressed + Recovery. Animals in the stressed groups were exposed to water avoidance stress for 1h/day for 10-days, with unstressed animals age-matched and housed under normal conditions. For recovery studies, animals were housed without stress exposure for an additional 10-days. Voiding behaviour was assessed periodically and animals sacrificed on day 10 (Unstressed and Stressed) or day 20 (Unstressed and Stressed + Recovery). Isolated whole bladder studies were used to assess compliance, urothelial mediator release and contractile responses. Exposure to stress increased plasma corticosterone levels almost three-fold (P<0.05) but this returned to baseline during the recovery period. Contractile responses of the bladder to carbachol and KCl were also increased following stress, and again fully recovered after a 10-day stress-free period. In contrast, stress increased urinary frequency four-fold (P<0.001), but this did not return fully to baseline during the recovery period. Bladder compliance was unchanged by stress; however, it was increased in the stressed + recovery group (P<0.05). Thus, following a stress-free period there is partial recovery of voiding behaviour, with an increase in bladder compliance possibly contributing to the compensatory mechanisms.
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Affiliation(s)
- Eliza G. West
- Faculty of Health Sciences and Medicine, Centre for Urology Research, Bond University, Gold Coast, Australia
| | - Catherine McDermott
- Faculty of Health Sciences and Medicine, Centre for Urology Research, Bond University, Gold Coast, Australia
| | - Russ Chess-Williams
- Faculty of Health Sciences and Medicine, Centre for Urology Research, Bond University, Gold Coast, Australia
| | - Donna J. Sellers
- Faculty of Health Sciences and Medicine, Centre for Urology Research, Bond University, Gold Coast, Australia
- * E-mail:
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2
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Chakrabarty B, Bijos DA, Vahabi B, Clavica F, Kanai AJ, Pickering AE, Fry CH, Drake MJ. Modulation of Bladder Wall Micromotions Alters Intravesical Pressure Activity in the Isolated Bladder. Front Physiol 2019; 9:1937. [PMID: 30687132 PMCID: PMC6335571 DOI: 10.3389/fphys.2018.01937] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 12/21/2018] [Indexed: 12/20/2022] Open
Abstract
Micromotions are phasic contractions of the bladder wall. During urine storage, such phasic activity has little effect on intravesical pressure, however, changed motile activity may underlie urodynamic observations such as detrusor overactivity. The potential for bladder motility to affect pressure reflects a summation of the overall movements, comprising the initiation, propagation, and dissipation components of micromotions. In this study, the influence of initiation of micromotions was investigated using calcium activated chloride channel blocker niflumic acid, and the effect of propagation using blockers of gap junctions. The overall bladder tone was modulated using isoprenaline. Isolated tissue strips and whole bladder preparations from juvenile rats were used. 18β-glycyrrhetinic acid was used to block gap junctions, reducing the amplitude and frequency of micromotions in in vitro and ex vivo preparations. Niflumic acid reduced the frequency of micromotions but had no effect on the amplitude of pressure fluctuations. Isoprenaline resulted in a reduction in pressure fluctuations and a decrease in pressure baseline. Using visual video data analysis, bladder movement was visible, irrespective of lack of pressure changes, which persisted during bladder relaxation. However, micromotions propagated over shorter distances and the overall bladder tone was reduced. All these results suggest that phasic activity of the bladder can be characterised by a combination of initiation and propagation of movement, and overall bladder tone. At any given moment, intravesical pressure recordings are an integration of these parameters. This synthesis gives insight into the limitations of clinical urodynamics, where intravesical pressure is the key indicator of detrusor activity.
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Affiliation(s)
- Basu Chakrabarty
- School of Physiology, Pharmacology and Neuroscience, Faculty of Life Sciences, University of Bristol, Bristol, United Kingdom
| | - Dominika A Bijos
- Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom.,Southmead Hospital, Bristol Urological Institute, Bristol, United Kingdom
| | - Bahareh Vahabi
- Department of Applied Sciences, University of West England, Bristol, Bristol, United Kingdom
| | - Francesco Clavica
- ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
| | - Anthony J Kanai
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Anthony E Pickering
- School of Physiology, Pharmacology and Neuroscience, Faculty of Life Sciences, University of Bristol, Bristol, United Kingdom.,Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom
| | - Christopher H Fry
- School of Physiology, Pharmacology and Neuroscience, Faculty of Life Sciences, University of Bristol, Bristol, United Kingdom
| | - Marcus J Drake
- Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom.,Southmead Hospital, Bristol Urological Institute, Bristol, United Kingdom
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3
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Lee S, Rose'meyer R, McDermott C, Chess-Williams R, Sellers DJ. Diabetes-induced alterations in urothelium function: Enhanced ATP release and nerve-evoked contractions in the streptozotocin rat bladder. Clin Exp Pharmacol Physiol 2018; 45:1161-1169. [PMID: 29935089 DOI: 10.1111/1440-1681.13003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 06/19/2018] [Accepted: 06/20/2018] [Indexed: 11/29/2022]
Abstract
Up to 80% of patients with diabetes mellitus develop lower urinary tract complications, most commonly diabetic bladder dysfunction (DBD). The aim of this study was to investigate the impact of diabetes on the function of the inner bladder lining (urothelium). Bladder compliance and intraluminal release of urothelial mediators, adenosine triphosphate (ATP) and acetylcholine (ACh) in response to distension were investigated in whole bladders isolated from 2- and 12-week streptozotocin (STZ)-diabetic rats. Intact and urothelium-denuded bladder strips were used to assess the influence of the urothelium on bladder contractility. Intraluminal ATP release was significantly enhanced at 2 weeks of diabetes, although not at 12 weeks. In contrast, intraluminal ACh release was unaltered by diabetes. Bladder compliance was also significantly enhanced at both 2 and 12 weeks of diabetes, with greatly reduced intravesical pressures in response to distension. Nerve-evoked contractions of bladder strips were significantly greater at 2 weeks of diabetes. When the urothelium was absent, nerve-evoked contractions were reduced, but contractions remained significantly elevated at lower frequencies of stimulation (<5 Hz) in diabetics. Interestingly, although relaxations of bladder strips to isoprenaline were unaltered by diabetes, removal of the urothelium unmasked significantly enhanced relaxations in strips from 2- and 12-week diabetic animals. In conclusion, diabetes alters urothelial function. Enhanced urothelial ATP release may be involved in the hypercontractility observed at early time points of diabetes. These alterations are time-dependent and may contribute to the mechanisms at play during the development of diabetic bladder dysfunction.
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Affiliation(s)
- Sophie Lee
- Centre for Urology Research, Faculty of Health Sciences and Medicine, Bond University, Gold Coast, QLD, Australia
| | - Roselyn Rose'meyer
- School of Medical Sciences, Griffith University, Gold Coast, QLD, Australia
| | - Catherine McDermott
- Centre for Urology Research, Faculty of Health Sciences and Medicine, Bond University, Gold Coast, QLD, Australia
| | - Russ Chess-Williams
- Centre for Urology Research, Faculty of Health Sciences and Medicine, Bond University, Gold Coast, QLD, Australia
| | - Donna J Sellers
- Centre for Urology Research, Faculty of Health Sciences and Medicine, Bond University, Gold Coast, QLD, Australia
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4
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Wang Y, Deng GG, Davies KP. Urothelial MaxiK-activity regulates mucosal and detrusor metabolism. PLoS One 2017; 12:e0189387. [PMID: 29281667 PMCID: PMC5744919 DOI: 10.1371/journal.pone.0189387] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 11/26/2017] [Indexed: 01/07/2023] Open
Abstract
There is increasing evidence for a role of MaxiK potassium channel-activity in regulating the metabolism and intracellular signaling of non-contractile bladder mucosal tissues. At present however no studies have determined the impact of urothelial MaxiK-activity on overall bladder metabolism. To address this we have investigated the effect of bladder lumen instillation of the MaxiK inhibitor, iberiotoxin (IBTX), on mucosal and detrusor metabolism using metabolomics. Since IBTX does not cross plasma membranes, when instilled into the bladder lumen it would only effect urothelially expressed MaxiK-activity. Surprisingly IBTX treatment caused more effect on the metabolome of the detrusor than mucosa (the levels of 17% of detected detrusor metabolites were changed in comparison to 6% of metabolites in mucosal tissue following IBTX treatment). In mucosal tissues, the major effects can be linked to mitochondrial-associated metabolism whereas in detrusor there were additional changes in energy generating pathways (such as glycolysis and the TCA cycle). In the detrusor, changes in metabolism are potentially a result of IBTX effecting MaxiK-linked signaling pathways between the mucosa and detrusor, secondary to changes in physiological activity or a combination of both. Overall we demonstrate that urothelial MaxiK-activity plays a significant role in determining mitochondrially-associated metabolism in mucosal tissues, which effects the metabolism of detrusor tissue. Our work adds further evidence that the urothelium plays a major role in determining overall bladder physiology. Since decreased MaxiK-activity is associated with several bladder pathophysiology's, the changes in mucosal metabolism reported here may represent novel downstream targets for therapeutic interventions.
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Affiliation(s)
- Yi Wang
- Department of Urology, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Gary G. Deng
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana, United States of America
| | - Kelvin P. Davies
- Department of Urology, Albert Einstein College of Medicine, Bronx, New York, United States of America
- Department of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, New York, United States of America
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Bravo G, Massa H, Rose'Meyer R, Chess-Williams R, McDermott C, Sellers DJ. Effect of short-term androgen deficiency on bladder contractility and urothelial mediator release. Naunyn Schmiedebergs Arch Pharmacol 2017; 390:547-556. [PMID: 28190243 DOI: 10.1007/s00210-017-1355-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 01/31/2017] [Indexed: 01/23/2023]
Abstract
In men, testosterone levels decline by 1% per year after the age of 40. Reduced androgen levels may directly contribute to lower urinary tract symptoms and bladder dysfunction, although the mechanisms are unclear. This study examined the effect of low testosterone and testosterone replacement on key mechanisms involved in local bladder function. Intraluminal release of the mediators ATP and ACh in response to bladder distension was measured in whole bladders from rats 8 weeks following castration, whilst bladder contractility was assessed using isolated strips. Human urothelial cells were cultured under low, physiological and supra-physiological testosterone conditions for 24 h or 5 days, and stretch-induced release of ATP and ACh was measured. Phasic contractile activity of bladder strips, agonist-induced reponses to carbachol and isoprenaline and nerve-evoked contractions were unaffected by castration. The acetylcholinesterase inhibitor neostigmine significantly increased amplitude of phasic activity only in bladder strips following castration, and this was prevented by testosterone replacement. Intraluminal ACh release following bladder distension was significantly reduced following castration, whilst ATP release was unaffected. In contrast, stretch-induced ATP release from urothelial cells was significantly enhanced in low testosterone conditions, whilst ACh release was unaltered. Testosterone-replacement to physiological levels prevented these changes. Whilst androgen deficiency of 8 weeks does not directly affect contractility of bladder smooth muscle, urothelial mediator release is sensitive to changes in testosterone. These changes in mediator release may be an early effect of the decline in testosterone and could affect sensory pathways in the longer term, contributing to the urinary symptoms and bladder dysfunction seen in androgen-deficient men.
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Affiliation(s)
- Giselle Bravo
- Centre for Urology Research, Faculty of Health Sciences and Medicine, Bond University, Queensland, Australia
| | - Helen Massa
- School of Medical Science, Griffith University, Queensland, Australia
| | | | - Russ Chess-Williams
- Centre for Urology Research, Faculty of Health Sciences and Medicine, Bond University, Queensland, Australia
| | - Catherine McDermott
- Centre for Urology Research, Faculty of Health Sciences and Medicine, Bond University, Queensland, Australia
| | - Donna J Sellers
- Centre for Urology Research, Faculty of Health Sciences and Medicine, Bond University, Queensland, Australia.
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Feng D, Nan H, Wang W, Yan L, Du P, Zuo L, Zhang K, Zhao M, Cui G. Expression and alteration of BK Ca channels in the sphincter of Oddi's from rabbits with hypercholesterolemia. Channels (Austin) 2017; 11:236-244. [PMID: 28102743 DOI: 10.1080/19336950.2017.1279369] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
This study aimed to investigate the expression and function of BKCa channels in the Sphincter of Oddi (SO) in a rabbit model of hypercholesterolemia (HC). New Zealand white rabbits were randomly divided into 2 groups: the control group was fed standard chow (n = 18) whereas the high-cholesterol group was fed cholesterol-enriched chow containing 1.5% cholesterol (n = 18). The serum cholesterol level was significantly greater in the HC groups than in the control group, but there was no significant difference in body weight between the control and HC groups. Although the total protein expression of BKCa α- and β1-subunit was not significantly different between the control and HC groups, the Tyr-phosphorylation of BKCa α-subunit was significantly decreased in the HC group than in the control group. In addition, hypercholesterolemia significantly increased Acetylcholine (ACh)-induced contraction of the SO rings. Pretreatment with 30 μM NS1619, a BKCa channel agonist, significantly reduced ACh-induced contraction of the SO rings in HC rabbits. Moreover, pretreatment with 100 μM Na3OV4, a protein tyrosine phosphatase inhibitor, significantly reduced ACh-induced contraction of the SO rings in HC rabbits, whereas it significantly increased upon pretreating with 10 μM Genistein, a tyrosine kinase inhibitor. Whole-cell patch clamp recordings showed that BKCa current density was significantly lower in SOSMCs from HC group than that from control group. Our findings suggest that hypercholesterolemia-induced downregulation of BKCa channel, and Tyr-phosphorylation of BKCa α-subunit may contribute to the hyperresponsiveness of the SO ring in HC rabbits.
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Affiliation(s)
- Dan Feng
- a Department of Radiology , Tangdu Hospital, Fourth Military Medical University , Xi'an , China
| | - Haiyan Nan
- a Department of Radiology , Tangdu Hospital, Fourth Military Medical University , Xi'an , China
| | - Wen Wang
- a Department of Radiology , Tangdu Hospital, Fourth Military Medical University , Xi'an , China
| | - Linfeng Yan
- a Department of Radiology , Tangdu Hospital, Fourth Military Medical University , Xi'an , China
| | - Pang Du
- a Department of Radiology , Tangdu Hospital, Fourth Military Medical University , Xi'an , China
| | - Lin Zuo
- a Department of Radiology , Tangdu Hospital, Fourth Military Medical University , Xi'an , China
| | - Kun Zhang
- b Department of Pharmacology, School of Pharmacy , Fourth Military Medical University , Xi'an , China
| | - Minggao Zhao
- b Department of Pharmacology, School of Pharmacy , Fourth Military Medical University , Xi'an , China
| | - Guangbin Cui
- a Department of Radiology , Tangdu Hospital, Fourth Military Medical University , Xi'an , China
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7
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Szasz T, Wenceslau CF, Burgess B, Nunes KP, Webb RC. Toll-Like Receptor 4 Activation Contributes to Diabetic Bladder Dysfunction in a Murine Model of Type 1 Diabetes. Diabetes 2016; 65:3754-3764. [PMID: 27650857 PMCID: PMC5127246 DOI: 10.2337/db16-0480] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 09/14/2016] [Indexed: 12/16/2022]
Abstract
Diabetic bladder dysfunction (DBD) is a common urological complication of diabetes. Innate immune system activation via Toll-like receptor 4 (TLR4) leads to inflammation and oxidative stress and was implicated in diabetes pathophysiology. We hypothesized that bladder hypertrophy and hypercontractility in DBD is mediated by TLR4 activation. Wild-type (WT) and TLR4 knockout (TLR4KO) mice were made diabetic by streptozotocin (STZ) treatment, and bladder contractile function and TLR4 pathway expression were evaluated. Immunohistochemistry confirmed the expression of TLR4 in human and mouse bladder. Recombinant high-mobility group box protein 1 (HMGB1) increased bladder TLR4 and MyD88 expression and enhanced contractile response to electrical field stimulation. Bladder expression of TLR4 and MyD88 and serum expression of HMGB1 were increased in STZ compared with control mice. Carbachol (CCh)-mediated contraction was increased in bladders from STZ mice, and TLR4 inhibitor CLI-095 attenuated this increase. Induction of diabetes by STZ in WT mice increased bladder weight and contractile responses to CCh and to electrical field stimulation. TLR4KO mice were not protected from STZ-induced diabetes; however, despite levels of hyperglycemia similar to those of WT STZ mice, TLR4KO STZ mice were protected from diabetes-induced bladder hypertrophy and hypercontractility. These data suggest that TLR4 activation during diabetes mediates DBD-associated bladder hypertrophy and hypercontractility.
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Affiliation(s)
- Theodora Szasz
- Department of Physiology, Augusta University, Augusta, GA
| | | | - Beth Burgess
- Department of Physiology, Augusta University, Augusta, GA
| | - Kenia P Nunes
- Department of Biological Sciences, Florida Institute of Technology, Melbourne, FL
| | - R Clinton Webb
- Department of Physiology, Augusta University, Augusta, GA
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Patra PB, Patra S. Research Findings on Overactive Bladder. Curr Urol 2015; 8:1-21. [PMID: 26195957 PMCID: PMC4483299 DOI: 10.1159/000365682] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2013] [Accepted: 01/09/2014] [Indexed: 12/19/2022] Open
Abstract
Several physiopathologic conditions lead to the manifestation of overactive bladder (OAB). These conditions include ageing, diabetes mellitus, bladder outlet obstruction, spinal cord injury, stroke and brain injury, Parkinson's disease, multiple sclerosis, interstitial cystitis, stress and depression. This review has discussed research findings in human and animal studies conducted on the above conditions. Several structural and functional changes under these conditions have not only been observed in the lower urinary tract, but also in the brain and spinal cord. Significant changes were observed in the following areas: neurotransmitters, prostaglandins, nerve growth factor, Rho-kinase, interstitial cells of Cajal, and ion and transient receptor potential channels. Interestingly, alterations in these areas showed great variation in each of the conditions of the OAB, suggesting that the pathophysiology of the OAB might be different in each condition of the disease. It is anticipated that this review will be helpful for further research on new and specific drug development against OAB.
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Affiliation(s)
- Phani B. Patra
- King of Prussia, Drexel University College of Medicine, Philadelphia, Pa., USA
| | - Sayani Patra
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pa., USA
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Petkov GV. Central role of the BK channel in urinary bladder smooth muscle physiology and pathophysiology. Am J Physiol Regul Integr Comp Physiol 2014; 307:R571-84. [PMID: 24990859 DOI: 10.1152/ajpregu.00142.2014] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The physiological functions of the urinary bladder are to store and periodically expel urine. These tasks are facilitated by the contraction and relaxation of the urinary bladder smooth muscle (UBSM), also known as detrusor smooth muscle, which comprises the bladder wall. The large-conductance voltage- and Ca(2+)-activated K(+) (BK, BKCa, MaxiK, Slo1, or KCa1.1) channel is highly expressed in UBSM and is arguably the most important physiologically relevant K(+) channel that regulates UBSM function. Its significance arises from the fact that the BK channel is the only K(+) channel that is activated by increases in both voltage and intracellular Ca(2+). The BK channels control UBSM excitability and contractility by maintaining the resting membrane potential and shaping the repolarization phase of the spontaneous action potentials that determine UBSM spontaneous rhythmic contractility. In UBSM, these channels have complex regulatory mechanisms involving integrated intracellular Ca(2+) signals, protein kinases, phosphodiesterases, and close functional interactions with muscarinic and β-adrenergic receptors. BK channel dysfunction is implicated in some forms of bladder pathologies, such as detrusor overactivity, and related overactive bladder. This review article summarizes the current state of knowledge of the functional role of UBSM BK channels under normal and pathophysiological conditions and provides new insight toward the BK channels as targets for pharmacological or genetic control of UBSM function. Modulation of UBSM BK channels can occur by directly or indirectly targeting their regulatory mechanisms, which has the potential to provide novel therapeutic approaches for bladder dysfunction, such as overactive bladder and detrusor underactivity.
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Affiliation(s)
- Georgi V Petkov
- Department of Drug Discovery and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina, Columbia, South Carolina
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Wang Y, Tar MT, Fu S, Melman A, Davies KP. Diabetes attenuates urothelial modulation of detrusor contractility and spontaneous activity. Int J Urol 2014; 21:1059-64. [PMID: 24846346 DOI: 10.1111/iju.12491] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Accepted: 04/13/2014] [Indexed: 02/04/2023]
Abstract
OBJECTIVES To investigate the effect of diabetes on urothelial modulation of bladder contractility. METHODS Bladder strips (urothelium intact or denuded) were prepared from 8-week-old streptozotocin-induced diabetic (n = 19) and non-diabetic control rats (n = 10). The effect of modulators of MaxiK (iberiotoxin and tetraethylammonium) and Kv7 (XE991 and retigabine) potassium channel activity were investigated for their effects on both carbachol-induced force generation and spontaneous contractile activity. RESULTS In bladder strips from non-diabetic animals, the presence of the urothelium resulted in marked sensitivity to carbachol-induced force generation by modulators of MaxiK and Kv7 channel activity, whereas in the diabetic animal urothelial sensitivity to these agents was significantly diminished. Urothelial-intact bladder strips from non-diabetic animals were more sensitive to modulators of Kv7 activity in reducing the amplitude of spontaneous phasic contractions than urothelial-denuded bladder strips, whereas in diabetic animals the presence or absence of the urothelium did not alter the sensitivity to modulators of Kv7 activity. Spontaneous activity in the presence of tetraethylammonium was not affected by the urothelium in bladder strips from either diabetic or non-diabetic animals. CONCLUSIONS The presence of the urothelium in bladders from non-diabetic animals modulates the activity of potassium blockers to affect bladder contractility, whereas in the diabetic bladder this effect is attenuated. These findings could help to explain the lack of success of pharmaceutical treatments targeting potassium channels to treat bladder pathology in patients with diseases imparing urothelial function.
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Affiliation(s)
- Yi Wang
- Department of Urology, Albert Einstein College of Medicine, Bronx, New York, USA
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