Frequency Of Non-voiding Contractions Research Articles

Improvement of neurogenic urinary dysfunctions in female rats treated with an injection of botulinum toxin A at the epicenter of the spinal cord injured site.

To assess the effect of an injection of botulinum toxin A (BoNT/A) at the epicenter of the spinal cord injury (SCI) site on the recovery of lower urinary tract function in female rats with thoracic SCI. Twenty-four female Wistar rats with Sham (laminectomy at T8/T9 level) or SCI (at T8/T9; 30 g compression for 5 s) were assigned into Sham-SS (injected with 5 µL of saline solution), Sham-BoNT/A (injected with 15 pg/rat, equivalent to 7.5 Units/kg of BoNT/A in 5 µL volume), SCI-SS (injured and injected with saline), SCI-BoNT/A (injured and injected with BoNT/A), N = 6 per group. Weekly evaluation of stereotyped micturition behavior, hind-limb nociception, and locomotor activity was performed 1 week before and during 6 weeks after surgery. Subsequently, all groups underwent simultaneous electromyography of the external urethral sphincter (EUS-EMG) and cystometric (CMG) studies. A compression SCI at the T8/T9 thoracic level significantly impairs sensory and locomotive functions, as well as stereotyped micturition behavior. However, these impairments were improved by BoNT/A injection after SCI. Neither injections of saline solution nor BoNT/A had an appreciable effect on the same parameters evaluated in the Sham groups. The combined EUS-EMG and CMG evaluations revealed important improvements of lower urinary tract physiology, particularly a reduction in the frequency of non-voiding contractions and the properties of EUS bursting activity indicated as the amplitude of the EUS-EMG signal and duration of burst electrical activity during effective voiding. The severe impairments on sensory and locomotive functions as well stereotyped micturition caused by an SCI could be potentially attenuated by an injection of a small amount of BoNT/A directly into the epicenter of the SCI region. A reduction in the release of neurotoxic neurotransmitters requiring the SNARE complex may be the mechanism triggered by BoNT/A to reduce neurotoxicity and hyperexcitability created in the SCI area to improve the survival of spinal cord cells involved in micturition.

Bone marrow mesenchymal stem cells therapy on bilateral pelvic nerve crush-induced voiding dysfunction in rats.

Neurogenic voiding dysfunction can be induced after radical pelvic surgery and severely affects patients' quality of life. This study aims to investigate the effects of bone marrow mesenchymal stem cells (BMSCs) on neurogenic voiding dysfunction in male rats and explore the underlying mechanisms. Thirty 4-week-old male Sprague-Dawley rats were randomly divided into three groups: (1) sham-operated (sham, n = 10), (2) intrabladder wall injection of phosphate buffer solution (PBS) after bilateral pelvic nerve crush (BPNC+PBS, n = 10), and (3) intrabladder wall injection of BMSCs after bilateral pelvic nerve crush (BPNC+BMSCs, n = 10). Four weeks postoperatively, functional and morphological examinations were performed. Compared to the sham group, BPNC rats manifested significant augmentation in the frequency of non-voiding contractions and postvoid residual and bladder capacity, and they had decreases in intravesical pressure and voiding efficiency. However, they were markedly improved after BMSC injection. Masson's trichrome staining showed that the ratio of collagen area in bladder wall tissue significantly increased in the BPNC+PBS group but was reduced following BMSC injection. BPNC increased the protein expression of TGF-β1, Smad2/3, and collagen I/III but decreased the expression of α-SMA. BMSC injection stimulated higher expression levels of α-SMA and lower expression levels of the other target proteins. The expression levels of vesicular acetylcholine transporters were reduced at 4weeks post-BPNC, whereas injection of BMSCs boosted the expression quantity. BMSC therapy suppressed detrusor fibrosis, improved intravesical pressure and voiding efficiency, and partially restored voiding function in male rats after BPNC.

The intracerebroventricular injection of lipopolysaccharide may induce neurogenic detrusor overactivity symptoms in mice.

We aimed to explore if the intracerebroventricular (i.c.v.) injection of lipopolysaccharide (LPS) was able to evoke the cognitive and locomotive impairment and detrusor overactivity (DO) symptoms in mice. This study compared the bladder function of mice that received the i.c.v. injection of LPS or saline. Specifically, basal pressure (BP), threshold pressure (TP), micturition pressure (MP), bladder capacity (BC), micturition volume (MV), bladder compliance (COM), frequency of micturition (MF), detrusor overactive index (DOI), frequency of non-voiding contractions (FNVCs), and amplitude of non-voiding contractions (ANVCs) were assessed by cystometry. The spontaneous voiding spot assay (VSA) was exerted to further assess the micturition patterns of mice. The Morris water maze (MWM) and the open field test (OFT) were used to detect the cognition and locomotive behaviors, respectively. Hematoxylin and eosin staining was conducted to evaluate the changes in morphology and histology of mice. The extent of injury in the prefrontal cortex was tested by using Nissl staining. The LPS-treated mice exhibited evidently DOcharacterized by the increase of MF, FNVCs, ANVCs, and DOI and the decrease of BC. The VSA further suggested that LPS induced urinary frequency and urinary incontinence in mice. Furthermore, neither signs of bladder inflammation nor the damage of bladder smooth muscle and urothelium in LPS-exposed mice was observed. LPS induced deficits in spatial learning, memory, and locomotor activity in mice. Neuronal cells in the prefrontal cortex were obviously lost in the LPS-treated mice. Acute neuroinflammation induced the cognitive and locomotive impairment and the neurogenic overactive bladder (NOAB) symptoms in mice. This novel animal model may contribute to further study the mechanisms of NOAB in neurodegenerative patients and assess the novel therapeutic strategies in the future.

Metformin abrogates the voiding dysfunction induced by prolonged methylglyoxal intake

Methylglyoxal (MGO) is a reactive carbonyl species found at high levels in blood of diabetic patients. The anti-hyperglycemic drug metformin can scavenger MGO and reduce the formation of advanced glycation end products (AGEs). Here, we aimed to investigate if MGO-induced bladder dysfunction can be reversed by metformin. Male C57/BL6 mice received 0.5% MGO in drinking water for 12 weeks, and metformin (300 mg/kg, daily gavage) was given in the last two weeks. The bladder functions were evaluated by performing voiding behavior assays, cystometry and in vitro bladder contractions. MGO intake markedly elevated the levels of MGO and fluorescent AGEs in serum and reduced the mRNA expression and activity of glyoxalase (Glo1) in bladder tissues. Glucose levels were unaffected among groups. MGO intake also increased the urothelium thickness and collagen content of the bladder. Void spot assays in conscious mice revealed an increased void volume in MGO group. The cystometric assays in anesthetized mice revealed increases of basal pressure, non-voiding contractions frequency, bladder capacity, inter-micturition pressure and residual volume, which were accompanied by reduced voiding efficiency in MGO group. In vitro bladder contractions to carbachol, α,β-methylene ATP and electrical-field stimulation were significantly greater in MGO group. Metformin normalized the changes of MGO and AGEs levels, Glo1 expression and activity, urothelium thickness and collagen content. The MGO-induced voiding dysfunction were all restored by metformin treatment. Our findings strongly suggest that the amelioration of MGO-induced voiding dysfunction by metformin relies on its ability to scavenger MGO, preventing its accumulation in blood.

PD27-07 BEDSIDE TO BENCHTOP RESEARCH UNCOVERS THE FUNCTIONAL ROLE OF HYPERPOLARIZATION-ACTIVATED CYCLIC NUCLEOTIDE-GATED GATED (HCN) CHANNELS IN AGING BLADDER PHENOTYPE

You have accessJournal of UrologyUrodynamics/Lower Urinary Tract Dysfunction/Female Pelvic Medicine: Basic Research & Pathophysiology (PD27)1 Sep 2021PD27-07 BEDSIDE TO BENCHTOP RESEARCH UNCOVERS THE FUNCTIONAL ROLE OF HYPERPOLARIZATION-ACTIVATED CYCLIC NUCLEOTIDE-GATED GATED (HCN) CHANNELS IN AGING BLADDER PHENOTYPE Nishant Singh, Irina Zabbarova, Anthony Kanai, Christopher Chermansky, Naoki Yoshimura, and Pradeep Tyagi Nishant SinghNishant Singh More articles by this author , Irina ZabbarovaIrina Zabbarova More articles by this author , Anthony KanaiAnthony Kanai More articles by this author , Christopher ChermanskyChristopher Chermansky More articles by this author , Naoki YoshimuraNaoki Yoshimura More articles by this author , and Pradeep TyagiPradeep Tyagi More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002020.07AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: The aging bladder phenotype in detrusor overactivity, detrusor underactivity or detrusor hyperactivity with impaired contractility patients is characterized by detrusor instability with or without the loss of bladder volume sensitivity. Since separate studies reported age related downregulation of Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels in mouse and human bladder, we examined the functional significance of age related reduction in HCN activity with multiple oral dosing of FDA approved HCN blocker, Ivabradine. METHODS: Aged male Fisher 344 rats (n=15) and young rats of both genders (n=15) were left untreated or treated daily with oral gavage of either vehicle or Ivabradine 6mg/kg (n=5) for 7 days prior to assessing nocturnal urination followed by awake cystometry on 7th day and quantitative RT-PCR and Western blot of HCN subtypes of untreated aged and young rats. RESULTS: Untreated aged aged rats (n=10) voided nearly double the volume of individual voids of young rats at night time (0.82±0.22 mL vs 0.41±0.12 mL, p<0.05), which was confirmed by a significant increase (p<0.05) in the micturition volume threshold (VT) in awake cystometry of aged rats. Increase in VT of aged rats coincided with a doubling of non-voiding contraction (NVC) frequency (p<0.05) while maximum voiding pressure (MVP) did not change with age. The age- related alterations in cystometry parameters correlated with the significant downregulation of cAMP sensitive HCN1and HCN2 subtype (40%) and the upregulation of cAMP insensitive HCN3 (60%) subtype. Ivabradine treatment significantly increased the VT (p<0.005), NVC frequency (p<0.001) and MVP (p<0.0001) in young and aged rats to different extents. CONCLUSIONS: A critical role for the altered bladder expression of HCN subtypes in the manifestation of aging bladder phenotype is supported by the dramatic changes in the bladder function following pharmacological blockade of HCN channels in young rats. The dramatic effect of Ivabradine on VT and MVP of aged rats in this bedside to benchtop research provides a basis for the therapeutic benefit of Ivabradine on detrusor underactivity of a male patient (Int Urol Nephrol, 40: 333, 2008). Source of Funding: NIA- AG062971 © 2021 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 206Issue Supplement 3September 2021Page: e446-e446 Advertisement Copyright & Permissions© 2021 by American Urological Association Education and Research, Inc.MetricsAuthor Information Nishant Singh More articles by this author Irina Zabbarova More articles by this author Anthony Kanai More articles by this author Christopher Chermansky More articles by this author Naoki Yoshimura More articles by this author Pradeep Tyagi More articles by this author Expand All Advertisement Loading ...

The Potential of Asiatic Acid in the Reversion of Cyclophosphamide-Induced Hemorrhagic Cystitis in Rats.

The purpose of this study was to determine if asiatic acid may act efficiently in the model of cyclophosphamide (CYP)-induced cystitis in rats. We performed experiments after administration of CYP (single dose 200 mg/kg, intraperitoneally), asiatic acid (30 mg/kg/day for 14 consecutive days, by oral gavage), or CYP plus asiatic acid, during which conscious cystometry, measurements of urothelium thickness and bladder edema, as well as selected biomarkers analyses were conducted. In rats that received asiatic acid together with CYP, a drop in bladder basal pressure, detrusor overactivity index, non-voiding contraction amplitude, non-voiding contraction frequency, and the area under the pressure curve were observed, when compared to the CYP group. Furthermore, a significant increase in threshold pressure, voided volume, intercontraction interval, bladder compliance, and volume threshold to elicit NVC were found in that group accordingly. Administration of the asiatic acid successfully restored concentrations of biomarkers both in bladder urothelium (BDNF, CGRP, OCT-3, IL-1β, IL-6, NGF, nitrotyrosine, malondialdehyde, TNF-α, SV2A, SNAP23, SNAP25, PAC-1, ORM1, occludin, IGFBP-3, HB-EGF, T–H protein, Z01, and HPX) and detrusor muscle (Rho kinase and VAChT) in CYP-treated rats. Finally, asiatic acid significantly decreased urothelium thickness and bladder oedema. Asiatic acid proved to be a potent and effective drug in the rat model of CYP-induced cystitis.

Silodosin improves functional consequences of lower urinary tract obstruction secondary to benign prostate hypertrophy, a proof of concept study in the spontaneously hypertensive rat supplemented with testosterone

BackgroundThe main purpose of this study is to investigate the effect of silodosin on the urodynamic consequences in a previously established model of lower urinary tract symptoms associated with benign prostate hyperplasia, the spontaneously hypertensive rats (SHR) supplemented with testosterone.MethodsThree groups of animals (8-week-old; n = 10/group) were considered: Wistar Kyoto (control) rats (WKY), SHR supplemented with testosterone at 3 mg/kg/day and treated with either vehicle (SHR-T, n = 10) or silodosin at 0.1 mg/kg/day (SHR-T + silodosin, n = 10) by oral gavage for 6 weeks. Cystometry experiments were performed. The bladder was harvested, weighed and paraffin-embedded for morphometric analysis. The prostate was also harvested and weighed.ResultsThe number of animals included in the analysis were n = 10/10 for WKY and n = 7–8/10 for each SHR rats supplemented with testosterone group. SHR-T displayed a significant decrease in the intercontraction interval, infused volume and mean flow rate whereas the frequency of non-voiding contractions was increased. Silodosin improved the voiding behavior of SHR-T by significantly increasing the intercontraction interval, the infused volume and the mean flow rate and decreasing the number of non-voiding contractions. SHR-T displayed a significant increase in prostate and bladder weights and a 15% increase in the detrusor wall area compared to WKY.ConclusionsChronic silodosin treatment relieved storage symptoms in SHR supplemented with testosterone and decreased the frequency of non-voiding detrusor contractions during the filling phase.

MP28-15 EFFECTS OF SINGLE BOUT ACUTE INTERMITTENT HYPOXIA PROTOCOLS ON REFLEX MICTURITION IN NAIVE AND SPINAL CORD-INJURED ADULT RATS

You have accessJournal of UrologyBladder & Urethra: Anatomy, Physiology & Pharmacology I (MP28)1 Apr 2020MP28-15 EFFECTS OF SINGLE BOUT ACUTE INTERMITTENT HYPOXIA PROTOCOLS ON REFLEX MICTURITION IN NAIVE AND SPINAL CORD-INJURED ADULT RATS William Collins*, Christine Wang, and Irene Solomon William Collins*William Collins* More articles by this author , Christine WangChristine Wang More articles by this author , and Irene SolomonIrene Solomon More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000000867.015AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Acute intermittent hypoxia (AIH) has been suggested as a potential therapy in spinal cord injury (SCI) since it can induce neural plasticity in both respiratory and non-respiratory somatic motor systems. Implementing the most commonly used AIH protocol consisting of a single bout of three 5-min episodes of hypoxia, we have previously demonstrated that AIH produces a sustained decrease in the frequency of reflex micturition events (rME) accompanied by an increase in micturition volume in both naïve rats and rats with moderate SCI as well as a sustained decrease in the frequency of non-voiding contractions in SCI rats. In the present study, we examine the effects of different single bout AIH protocols that keep the total duration of hypoxia (15 min) constant but differ in timing and number of hypoxic episodes on lower urinary tract (LUT) function in naïve and SCI rats. METHODS: We assessed the effects of three single bout AIH protocols on bladder intravesical pressure (BP) and void volume recorded under urethane anesthesia (1.4 g/kg) in naïve and mid-thoracic moderate contusion SCI (4-week survival) rats during continuous infusion of saline (0.04 ml/min) into the bladder to elicit rMEs. The AIH protocols implemented consisted of alternating exposures of hypoxia (12% O2) and normoxia using the following: (1) three 5-min episodes, (2) five 3-min episodes, and (3) ten 1.5-min episodes. Following the AIH exposure, data acquisition continued for up to 120 minutes while the rats continued to breathe room air. RESULTS: In both naïve and SCI rats, each single bout AIH protocol produced a comparable decrease in rME frequency and increase in void volume that persisted for up 120 min post-AIH. Moreover, in SCI rats, each of the protocols was equally effective in reducing the ratio of non-voiding/voiding bladder contractions. Single bout AIH exposure also produced transient increases in both bladder contraction threshold BP and minimum BP. Modulation of LUT behavior during individual exposures to hypoxia and immediately following each hypoxic episode (“off effect”) were also observed, with the intensity of the “off effect” tending to be lower following short duration (e.g., 10 x 1.5-min) hypoxic exposures. CONCLUSIONS: Our observations suggest that while each single bout AIH protocol is effective in improving micturition and reducing non-voiding bladder contractions in SCI rats, subtle differences in magnitude and/or timing were noted across the protocols. Source of Funding: DOD CDMRP W81XWH-17-1-0260; NIH NS096514 © 2020 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 203Issue Supplement 4April 2020Page: e425-e426 Advertisement Copyright & Permissions© 2020 by American Urological Association Education and Research, Inc.MetricsAuthor Information William Collins* More articles by this author Christine Wang More articles by this author Irene Solomon More articles by this author Expand All Advertisement PDF downloadLoading ...

Pathophysiological changes of the lower urinary tract behind voiding dysfunction in streptozotocin-induced long-term diabetic rats

We evaluated pathophysiological characteristics of the lower urinary tract dysfunction in a streptozotocin (STZ)-induced diabetic rat model. STZ (60 mg/kg) was injected intraperitoneally into male Wistar rats. In vitro bladder muscle strip experiments, in vivo cystometry, and simultaneous recordings of bladder pressure + urethral perfusion pressure (BP + UPP) with or without intravenous administration of L-arginine (300 mg/kg) or tadalafil (0.03 mg/kg) were performed at several time points. In vitro muscle strip experiments demonstrated that diabetic rats had significantly higher contractile responses to carbachol at 4–16 weeks, and a tendency for higher contractile responses to electrical field stimulation at 4–12 weeks, but this was reversed at 16 weeks. Diabetic rats had significant increases in voided volume, residual volume, bladder capacity, maximal voiding pressure, and amplitude and frequency of non-voiding contractions at 16 weeks. Tadalafil decreased the residual volume in diabetic rats. Diabetic rats had significantly higher UPP nadir and mean UPP during high-frequency oscillation at 16 weeks, which were reversed by tadalafil or L-arginine administration. The present results suggest that urethral relaxation failure, probably related to impairment of the NO/cGMP signalling pathway, rather than bladder contractile dysfunction may be a prominent cause for voiding dysfunction in STZ-induced chronic diabetic rats.

Combination phosphodiesterase type 4 inhibitor and phosphodiesterase type 5 inhibitor treatment reduces non-voiding contraction in a rat model of overactive bladder.

IntroductionCurrent treatments for overactive bladder (OAB) are often discontinued due to side effects or lack of efficacy. The goal of this study was to determine if combining a phosphodiesterase type 4 inhibitor (PDE4i); with a type 5 inhibitor (PDE5i); would have a beneficial effect on OAB symptoms and if a reduced dose of PDE4i in combination with PDE5i could also provide a beneficial effect in OAB. We hypothesized that PDE5i and PDE4i combination treatment could be utilized to reduce non-voiding contractions and smooth muscle disruption in a rat model of OAB.MethodsFifty-eight age-matched Sprague-Dawley rats underwent PBOO and daily gavage with PDE4i alone (roflumilast; 1mg/kg), PDE5i alone (tadalafil;10mg/kg), high dose combination (PDE4i 1mg/kg, PDE5i 10mg/kg), low dose combination (PDE4i 0.2mg/kg, PDE5i 10mg/kg), or vehicle for 28 days. Fourteen animals underwent sham PBOO with vehicle. Rats underwent conscious and anesthetized cystometry 28 days after PBOO and were euthanized for qualitative bladder histology. One-way ANOVA on ranks with a Dunn’s post hoc test was used to indicate statistically significant differences between groups (p<0.05).ResultsBladder & urethral weight was significantly increased after PBOO with vehicle, PDE4i alone, and PDE5i alone, but not with either combination treatment. Frequency of non-voiding contractions during both conscious and anesthetized cystometry increased significantly after PBOO with vehicle, but not after PDE4i or high dose combination treatments compared to sham PBOO. Threshold pressure for voiding was significantly decreased with high dose combination compared to vehicle. PBOO treated with PDE4i alone or high dose combination showed less bladder smooth muscle fibrosis than vehicle, PDE5i alone, or low dose combination treatments.ConclusionA PDE4i and PDE5i combination treatment has potential benefit in reducing OAB symptoms, but future research is needed.

Blebbistatin reveals beneficial effects on the cystometric parameters in an animal model of detrusor overactivity

The aims of the study were to determine the effectiveness of blebbistatin (BLEB) on detrusor overactivity (DO) in an animal model induced by retinyl acetate (RA) and, because of potential urothelial permeability, to evaluate the degenerative impact of BLEB on the urothelium. Three days after RA instillation into the urinary bladder, BLEB was administered into the bladder and immediately after cystometric assessment was performed. Furthermore, Evans Blue extravasation into bladder tissue and urothelium thickness were measured. Sixty female Wistar rats were used and randomly assigned to one of four groups (n = 15 in each group): (1) control, (2) RA, (3) BLEB, and (4) RA + BLEB. RA administration induced changes in cystometric parameters reflecting DO, as previously reported. Treatment with BLEB did not significantly alter cystometric parameters in rats which did not receive RA. Administration of BLEB to rats pretreated with RA reversed changes in cystometric parameters induced by RA in basal pressure, threshold pressure, detrusor overactivity index, amplitude of nonvoiding contractions, frequency of nonvoiding contractions, voided volume, volume threshold, intercontraction interval, bladder compliance, and volume threshold to elicit nonvoiding contractions. There were no significant differences in Evans Blue extravasation into bladder tissue or urothelium thickness between the groups. The current research provides new data on the possible utility of blebbistatin in the pharmacotherapy of DO, which is an important feature of overactive bladder (OAB). Further studies in human patients with DO/OAB are warranted to confirm these preclinical results.

Menthol ameliorates voiding dysfunction in types I and II diabetic mouse model.

Overactive bladder (OAB) is one of the most common complications of both type 1 (T1DM) and type 2 diabetes mellitus (T2DM). In healthy conditions, menthol infused intravesically reduces the threshold for initiating micturition reflex, but no study evaluated its effects in diabetic conditions. Therefore, we have used mouse models of T1DM and T2DM to evaluate the effects of menthol on cystometric alterations and increased bladder contractility in vitro. For T1DM induction, male C57BL6 mice were injected with streptozotocin (STZ) and evaluated after 4 weeks. For T2DM induction, mice were fed with high-fat diet (HFD) for 12 weeks to induce obesity. Urodynamic profiles were assessed by filling cystometry through the infusion of menthol (100 µM for 30 min) or vehicle (DMSO 0.1%). Contractile responses to carbachol, potassium chloride (KCl), and electrical-field stimulation (EFS) were measured in isolated bladders after 20 min incubation with menthol (100 µM) or vehicle. Filling cystometry showed that STZ-injected mice exhibited higher bladder capacity, threshold pressure, and non-voiding contractions (NVCs), which were significantly reduced by menthol infusion. The increased voiding frequency in STZ group were unaffected by menthol. In HFD-fed obese mice menthol significantly attenuated the increased threshold pressure and NVC frequency, but unaffected the changes of voiding frequency. In both STZ-injected and HFD-fed mice, incubation of isolated bladders with menthol normalized the enhanced contractile responses to carbachol, KCl, and EFS stimulation. Menthol may be a potential pharmacological option for the treatment of OAB as a consequence of T1DM and T2DM.

Administration of leuprolide acetate, a GnRH agonist, improves urodynamic parameters in ovariectomized rats.

To evaluate the effects of a treatment with leuprolide acetate (LA) on bladder overactivity as well as the expression of gonadotropin releasing hormone receptor (GnRH-R), and neurofilaments NF68 and NF200 in female rats with overactive bladder induced by castration. Changes in the urodynamic parameters were determined in SHAM, ovariectomized (OVX) and ovariectomized rats treated with LA (OVX-LA). A semi-quantitative analysis for the expression pattern of GnRH-R and neurofilaments NF68 and NF200 were determined. Forty-three days after ovariectomy, rats from the OVX group have significant lower values for intercontractile interval (ICI) and compliance (C); as well as higher values for basal bladder pressure (BP) and frequency of non-voiding contractions (NVC). The systemic application of LA increased voiding volume (Vv) and pressure threshold (ThP) in the OVX-LA animals. The application of LA reduced the high frequency of NVC in the OVX rats. No significant differences were found for Vv and NVCs between the OVX-LA vs SHAM groups. At the mid part of the bladder, the presence of GnRH-R was evidenced in the urothelium of the SHAM group. The OVX animals showed different pattern of immunolabeling for GnRH-R as well as for neurofilaments NF200 and NF68, whereas in the OVX-LA group the immunofluorescence pattern was similar to the one seen in SHAM bladders (P < 0.05 for OVX vs OVX + LA). the results suggest that systemic application of LA can improve bladder dysfunction in castrated rats, and perhaps considered as a treatment for overactive bladder conditions secondary to menopause.

The frequency spectrum of bladder non-voiding activity as a trigger-event for conditional stimulation: Closed-loop inhibition of bladder contractions in rats.

To test the hypothesis that the frequency of bladder non-voiding contractions (NVCs) can be used as a trigger event for closed-loop conditional inhibition of detrusor contractions via tibial nerve (TN) or dorsal penile nerve (DPN) stimulation. In urethane anaesthetized male Wistar rats, the bladder was filled continuously with saline to evoke contractions. To test the plausibility of conditional inhibition via the TN, electrical stimulation was switched on manually when the pressure increased above a threshold of 10 cmH2 0 above the baseline. For testing conditional stimulation via the DPN, the pressure signal was continuously stored and a baseline threshold, the area under the curve (AUC) of the amplitude spectrum in the 0.2-20 Hz range of a 5 s window at the beginning of filling was calculated. When the AUC of subsequent pressure windows superseded the baseline threshold, the DPN was automatically stimulated. TN stimulation failed to inhibit evoked voiding contractions. The NVC frequency spectrum based DPN stimulation successfully inhibited 70% of the evoked contractions and resulted in a 45% increase in bladder capacity (BC). While, conditional TN stimulation failed to suppress bladder contractions, DPN stimulation, automatically triggered by an increased frequency of bladder non-voiding activity, resulted in bladder inhibition, and a consequential increase in BC. This study demonstrates the plausibility of using the frequency of NVCs as a trigger event for conditional inhibition of detrusor contractions.

The influence of duloxetine on detrusor overactivity in rats with depression induced by 13-cis-retinoic acid

Introduction and hypothesisThe aim of this study was to assess the efficacy of duloxetine in an animal model of detrusor overactivity induced by depression.MethodsAfter 6 weeks of 13-cis-retinoic acid administration at a dose of 1 mg/kg/day, rats were given duloxetine at a dose of 1 mg/kg. This was followed by conscious cystometry, a forced swim test, and locomotor activity measurement. The levels of corticotropin-releasing factor (CRF) in the hypothalamus, amygdala and plasma were also determined.ResultsDuloxetine treatment led to a reduction in detrusor overactivity symptoms induced by the retinoid. Decreases were observed in cystometric parameters including the detrusor overactivity index, and the amplitude and frequency of nonvoiding contractions, while increases were seen in bladder compliance and the volume threshold to elicit nonvoiding contractions. No statistically significant differences were found in basal pressure, threshold pressure, micturition voiding pressure, postvoid residual , volume threshold, voiding efficiency, intercontraction interval, bladder contraction duration or relaxation time. Duloxetine also reduced the immobility time to that observed in control animals, while it did not affect locomotor activity. Its effects also included lowering of the CRF levels in the hypothalamus, amygdala and plasma, which increased following the prior administration of the retinoid. The plasma level of 13-cis-retinoic acid in rats corresponded to the levels found in humans.ConclusionsThis is the first study showing the efficacy of duloxetine in an animal model of detrusor overactivity induced by depression. Further studies in patients with detrusor overactivity and coexisting depression are warranted to confirm these experimental results.

Neurogenic bladder dysfunction does not correlate with astrocyte and microglia activation produced by graded force in a contusion-induced spinal cord injury.

Rodent models for the study of neurogenic bladder dysfunction after spinal cord injury (SCI) are difficult to standardize, particularly when evaluating the specific contribution of the SCI to end-organ function. The purpose of this study was to evaluate the degree of bladder dysfunction associated with a highly reproducible, contusion-induced SCI in female rats. An infinite horizon impactor was used to create a contusion SCI with a magnitude of either 100 or 150 kDyne at the T8/T9 thoracic region of female Sprague-Dawley rats. Locomotor function, and the presence of astrocytes (positive regions for Glial Fibrillary Acidic Protein) and microglia (positive cells for the integrin CD11b) at the SCI site were determined at four weeks after SCI. Similarly, cystometric properties were characterized in urethane anesthetized rats at four weeks post-SCI. The significant increases in astrocyte and microglia in the T8/T9 region in all of the SCI animals did not correlate with locomotor impairment or bladder dysfunction. After performing the cystometric studies substantial differences were found in both SCI groups when compared to intact animals, specifically a high frequency of non-voiding contractions, different durations for intraluminal pressure-high frequency oscillations, intercontractile intervals, impaired micturition volumes, and estimated voiding efficiency. These results suggest that a contusion SCI can increase microglia and astrocyte activation without a strong association with bladder dysfunction. The present study will be important for precise considerations about correlating the intensity of an SCI with impairment outcomes at both locomotor or organ function levels.

Rho kinase inhibition ameliorates cyclophosphamide-induced cystitis in rats

Hemorrhagic cystitis often develops in patients treated with cyclophosphamide (CYP). Studies have indicated that Rho kinase (ROCK) inhibitors may suppress detrusor overactivity symptoms and possess anti-inflammatory properties. The aim of the present study was to investigate whether inhibition of ROCK reduces cystometric and histopathological changes associated with CYP-induced cystitis. The rats received GSK 269962, a ROCK inhibitor, at a dose of 30 mg/kg daily, or vehicle for 7 days. Then, acute chemical cystitis leading to bladder overactivity was induced by CYP injection (200 mg/kg i.p.). Following CYP injection, cystometric studies with physiological saline were performed. Moreover, bladder edema (by the Evans Blue dye leakage technique) and urothelium thickness were measured. CYP injection resulted in a significant increase in cystometric parameters: basal pressure, threshold pressure, bladder contraction duration, relaxation time, detrusor overactivity index, non-voiding contractions amplitude, and non-voiding contractions frequency as well as increased Evans Blue extravasation into bladder tissue, whereas micturition voiding pressure, voided volume, post-void residual, volume threshold, intercontraction interval, bladder compliance, and volume threshold to elicit non-voiding contractions as well as urothelium thickness were significantly decreased in CYP-injected rats. Administration of GSK 269962 normalized the abovementioned CYP injection-induced changes. Inhibition of ROCK was found to ameliorate CYP-induced detrusor overactivity and bladder inflammation. Our data indicate uroprotective effects following ROCK inhibition, which further suggests that this strategy may become an interesting pharmacological tool to prevent urinary adverse effects in patients treated with chemotherapy using CYP.

LB-S&T-37 INTERACTION OF TRPV4 AND SK3 CHANNELS IN DETRUSOR PDGFR?+ CELLS CONTROLS BLADDER FILLING

You have accessJournal of UrologyLate-Breaking S&T Poster1 Apr 2016LB-S&T-37 INTERACTION OF TRPV4 AND SK3 CHANNELS IN DETRUSOR PDGFR?+ CELLS CONTROLS BLADDER FILLING Haeyeong Lee, Byoung Koh, Robert Corrigan, Lauren Peri, Brian Perrino, Toby Chai, Kenton Sanders, and Sang Don Koh Haeyeong LeeHaeyeong Lee More articles by this author , Byoung KohByoung Koh More articles by this author , Robert CorriganRobert Corrigan More articles by this author , Lauren PeriLauren Peri More articles by this author , Brian PerrinoBrian Perrino More articles by this author , Toby ChaiToby Chai More articles by this author , Kenton SandersKenton Sanders More articles by this author , and Sang Don KohSang Don Koh More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2016.03.118AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Recently we reported the functional expression of SK channels in detrusor PDGFRa+ cells. This cell does not display voltage dependent Ca2+ channels. Finding the source of extracellular Ca2+ influx is critical for activation of SK channels. TRPV are relatively more Ca2+ permeable. In previous papers, TRPV4 KO mice demonstrated an increase in frequency of non voiding contractions (NVCs). The mechanism of this phenotype has not been studied. Thus, we hypothesized that TRPV4 channels are main source of Ca2+ influx to activate SK channels during filling. METHODS We applied molecular approaches, protein chemistry, patch clamp techniques, isometric force measurement, ex vivo cystometry, Ca2+ imaging techniques. PDGFRa/eGFP and C57BL/6 mice were used for cell sorting and patch clamp. Molecular expression of Trp channels and protein protein interaction between TRPV4 and SK3 channels were examined. Effects of TRPV4 agonist and antagonist were also examined on PDGFRa+ cells and smooth muscle cells (SMC) using patch clamp approaches. Detrusor contractility, ex vivo cystometry and Ca2+ imaging analysis were employed for functional analysis. RESULTS Quantitative analysis of transcripts demonstrated that Trpv4 is highly expressed in murine PDGFRa+ cells. In patch clamp experiments a TRPV4 channel agonist, GSK1016790A (GSK), activated TRPV4 current that was linked to activation of SK current. Under current clamp, GSK induced membrane hyperpolarization of detrusor PDGFRa+ cells. GSK activated SK currents were blocked by TRPV4 antagonists. Detrusor SMCs were unresponsive to GSK. In contractile experiments, GSK decreased phasic contractions in a dose dependent manner. TRPV4 antagonist increased phasic contractions. In ex vivo cystometry, GSK increased non-voiding contractions in the presence of apamin. In contrast TRPV4 antagonist increased NVCs, and NVCs were also elevated significantly in bladders of Trpv4 KO mice. Proximity ligation assays demonstrated protein protein interactions between TRPV4 and SK3 channels. GSK increased Ca2+ transients only in PDGFRa+ cells but not in SMC. CONCLUSIONS TRPV4 and SK channels are functionally interacted closely in plasma membrane of PDGFRa+ cells. Ca2+ influx through TRPV4 channels directly activates SK channels. Since TRPV4 are mechanosensitive channels, activation of TRPV4 during bladder filling stabilize membrane potentials and prevent detrusor overactivity. © 2016FiguresReferencesRelatedDetails Volume 195Issue 4SApril 2016Page: e352 Advertisement Copyright & Permissions© 2016MetricsAuthor Information Haeyeong Lee More articles by this author Byoung Koh More articles by this author Robert Corrigan More articles by this author Lauren Peri More articles by this author Brian Perrino More articles by this author Toby Chai More articles by this author Kenton Sanders More articles by this author Sang Don Koh More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

The Influence of Maxacalcitol, Vitamin D3 Analog, on Detrusor Overactivity in Conscious Rats

To test the hypothesis that maxacalcitol, vitamin D3 analog, would ameliorate detrusor overactivity (DO) induced by retinyl acetate instillation; to test the outcome of the combined administration of maxacalcitol and the rho kinase inhibitor - GSK 269962, amlodipine besylate, or oxybutynin chloride in this model. The rats were treated with maxacalcitol for 14 days. Then, cystometric studies were performed during which the animals were administered test compounds. Maxacalcitol in a dose of 30 but not 15 µg/kg/day induced reduction in DO index, non-voiding contractions frequency (FNVC), and amplitude (ANVC), while increasing volume threshold to elicit non-voiding contractions (VTNVC). The 14-day-long administration of maxacalcitol at a dose of 15 µg/kg/day to animals, followed by GSK 269962 at a single dose of 10 mg/kg, led to a statistically significant reduction of intercontraction interval and bladder compliance, and an increase in DO index, without any effect on ANVC, FNVC, and VTNVC. The assessment of the combined effect of maxacalcitol (15 µg/kg/day) and amlodipine besylate (0.25 mg/kg) demonstrated an increase in intercontraction interval, bladder compliance and VTNVC, with a decrease in FNVC. No statistically significant changes were found in DO index and ANVC. The combined outcome of administering maxacalcitol (15 µg/kg/day) and oxybutynin chloride (0.25 mg/kg) did not show any statistically significant value of the measured cystometric parameters. The outcomes of maxacalcitol administration can be the result of 3 mechanisms, that is, the upregulation of L-type Ca(2+) channels, the inhibition of the rho kinase pathway, and a so far unknown central mechanism.

Ovariectomy May Induce Detrusor Overactivity in Rats: The Therapeutic Role of Rho Kinase Inhibition

To verify the impact of ovariectomy (OVX) on the micturition cycle in conscious rats; to examine the influence of rho kinase (ROCK) inhibition on the bladder detrusor in OVX rats; to assess the effect of the joint administration of the ROCK inhibitor (GSK 269962) and solifenacin succinate (SOL) to these animals. The impact of OVX or a single dose of GSK 269962 and/or SOL on the cystometric parameters was assessed 28 days after the procedure. OVX caused an increase in detrusor overactivity index, amplitude, and frequency of nonvoiding contractions, along with a decrease in voided volume, volume threshold, intercontraction interval, bladder compliance, and volume threshold to elicit nonvoiding contractions. GSK 269962 administered in a dose of 10 mg/kg (but not 5 mg/kg) or SOL in a dose of 0.03 mg/kg (but not 0.015 mg/kg) triggered an increase in voided volume, volume threshold, intercontraction interval, bladder compliance, and volume threshold to elicit nonvoiding contractions, along with a decrease in detrusor overactivity index, amplitude, and frequency of nonvoiding contractions. A combined administration of GSK 269962 (5 mg/kg) and SOL (0.15 mg/kg), in doses ineffective in monotherapy, triggered a reversal in the OVX-induced cystometric changes. It appears that ROCK inhibitors can become an alternative worth considering in overactive bladder syndrome treatment, especially in the light of the findings pointing to the decreased efficiency of antimuscarinic drugs in the overactive bladder syndrome treatment of postmenopausal women.