Effect of tamsulosin on urethral tone in healthy male cats.

OBJECTIVES: Alpha-adrenergic antagonists are commonly used to prevent recurrent urethral obstruction in cats with mixed reports of efficacy. No published data on tamsulosin use in cats are available. The objective of this study was to measure changes in urodynamic parameters and blood pressure in five healthy male cats before and after administration of tamsulosin orally for 4 and 10 days. METHODS: Five young healthy adult male cats from a research colony were administered tamsulosin at 0.1 mg/cat PO q24h for 10 days. Urethral pressure profile and blood pressure measurements were performed before treatment and approximately 6 h after treatment on days 4 and 10. Maximum urethral closure pressure (MUCP) for the prostatic and penile urethra, functional urethral length (FPL), functional area (FA) and systolic blood pressures were recorded and compared between the time points. RESULTS: Significant changes in blood pressure on day 4 (121.1 mmHg ± 20.2 mmHg) and on day 10 (112.6 mmHg ± 14.9 mmHg) compared with day 0 (141.1 mmHg± 33.4 mmHg) were not detected (P = 0.18) in anesthetized cats. No significant difference in MUCP, FA or FPL measurements were detected among baseline, day 4 and day 10 of treatment. Hematuria and transient pollakiuria were induced in two cats with 3.5 Fr urethral catheters. CONCLUSIONS AND RELEVANCE: Tamsulosin at 0.1 mg/cat PO q24h did not induce hypotension in healthy cats. Urodynamic testing performed 6 h after the tamsulosin pill was administered did not detect consistent decreases in urodynamic functions induced by tamsulosin. Repeated catheterization of tom cats with 3.5 Fr catheters may induce significant urethral trauma.

Effect of prazosin on feline recurrent urethral obstruction.

OBJECTIVES: The aim of this study was to determine if male cats treated with 7 days of prazosin following relief of urethral obstruction (UO) experienced decreased rates of recurrent urethral obstruction (rUO) within 30 days vs those treated with 7 days of placebo. METHODS: All castrated male cats presenting for the first time with UO from May 2014 to August 2017 were eligible for enrollment. Exclusion criteria included the administration of medications or passage of a urinary catheter prior to referral, the presence of heart disease or hypertension requiring medication, prior treatment with glucocorticoids, non-steroidal anti-inflammatory medications, prazosin or phenoxybenzamine, or radiographic identification of cystoliths. Cats were treated with standardized anesthetic and analgesic protocols, standardized indwelling urinary catheter management, and were hospitalized for care. A random numbers table was generated prior to study initiation and cats were randomized to receive either prazosin (0.5 mg PO q12h for 7 days) or placebo in a blinded fashion. A 30-day follow-up with owners via telephone was performed to identify the rate of rUO. Cats that did not receive the full course of study medication were removed from the analysis. The study was unblinded at the end of data collection. RESULTS: Eighty cats were enrolled and 65 cats completed the study; 12 were excluded because they did not receive the study medication. Sixteen of 65 cats experienced rUO (25%). Of the 16 cats experiencing rUO, five received placebo (n = 5/28 [18%]) and 11 received prazosin (n = 11/37 [30%]). Ten of the cats that experienced rUO reblocked while still hospitalized. There was no significant difference in frequency of rUO in cats treated with prazosin vs placebo (P = 0.27). CONCLUSIONS AND RELEVANCE: Prazosin administered at 0.5 mg PO q12h did not decrease the rate of rUO in this population of obstructed male cats vs placebo. These results further support evidence suggesting that prazosin may not be beneficial in prevention of feline rUO.

A prospective randomized study of efficacy of 2 treatment protocols in preventing recurrence of clinical signs in 51 male cats with obstructive idiopathic cystitis.

BACKGROUND: Urethral obstruction (UO) is a common complication of feline idiopathic cystitis (FIC). Robust treatment recommendations to prevent its recurrence are scarce. OBJECTIVES: To evaluate meloxicam treatment for prevention of clinical recrudescence in male cats with obstructive FIC. ANIMALS: Fifty-one client-owned cats. METHODS: Prospective, randomized clinical trial. Every male cat with FIC-associated UO was deemed eligible for the study and was recruited during hospitalization. After discharge, cats were treated with phenoxybenzamine and alprazolam for 2 weeks, with (24 cats) or without (27 cats) low-dose meloxicam (0.025 mg/kg/day PO) and monitored for 6 months. RESULTS: Cumulative number (%) of cats with recurrent UO at 10 days, 1-, 2-, and 6-months after discharge was 1 (2%), 2 (4%), 4 (8%), and 8 (16%), respectively. Overall, 12 (24%) cats experienced signs of recurrent FIC within 6 months, with (8 cats) or without (4 cats) concurrent UO. No difference in the cumulative incidence of UO within 6 months was detected with addition of meloxicam (odds ratio [95% confidence interval], 0.63 [0.13-2.97]; P = .70). All cats were alive at 6 months. CONCLUSIONS AND CLINICAL IMPORTANCE: No clinical benefit was detected with the addition of low-dose meloxicam to phenoxybenzamine and alprazolam treatment for 2 weeks after discharge. Nevertheless, this study was underpowered to identify potential differences, and its findings must be corroborated in larger studies.

Holter Monitoring (24-Hour ECG) Parameter Dynamics in Patients with Ischemic Heart Disease and Lower Urinary Tract Symptoms Due to Benign Prostatic Hyperplasia.

INTRODUCTION: This study examined the dynamics of 24-h electrocardiogram (ECG) monitoring parameters (Holter monitoring) in patients with ischemic heart disease (IHD) before and after conservative or surgical treatment of patients with voiding and storage lower urinary tract symptoms (LTS) due to benign prostatic hyperplasia (BPH). METHODS: A total of eighty-three 57 to 81-year-old (mean age 70.4 ± 5.75 years) patients with LUTS/BPH and accompanying IHD were examined and treated at the Institute of Urology and Human Reproductive Health and Clinic of Cardiology of Sechenov University. All patients received recommended cardiac therapy at least 6 months before inclusion in the study. RESULTS: Our study demonstrated that there is correlation between voiding and storage LUTS/BPH and Holter-detected cardiac impairments in patients with IHD/BPH. These data make it possible to consider LUTS/BPH (voiding and storage) as a factor in the additional functional and psychological load on the activity of patients with ischemic heart disease. Improvement of voiding and storage LUTS due to BPH and objective parameters of urination (Qmax) in patients treated with alpha-1 adrenoceptor blocker tamsulosin correlated with improvement of 24-h ECG monitoring parameters (Holter monitoring) in 72% of patients. Improvement of 24-h ECG monitoring parameters (Holter monitoring) 1 month after transurethral resection of the prostate (TURP) in IHD/BPH patients and indications for surgical treatment was observed in 65.7%. Negative dynamics of the Holter-based ECG was not registered in patients who were operated on. CONCLUSION: Holter monitoring helps to identify groups of patients in whom urinary impairments caused by prostatic hyperplasia negatively affect the course of IHD. Restored urination (either conservatively or operatively) in patients with BPH in 72% of cases decreased the number of fits of angina, thus influencing favourably the course of IHD. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03856242.

The effect of prazosin on outcome in feline urethral obstruction.

OBJECTIVE: To determine whether prazosin administration following urethral obstruction (UO) reduces the risk for recurrent urethral obstruction (rUO) or lower urinary tract signs, and to document adverse effects associated with prazosin use in cats. DESIGN: Double-blinded, prospective, interventional study. SETTING: University teaching hospital. ANIMALS: A population of 47 consecutive male cats with UO not associated with urinary tract calculi >2 mm in diameter. INTERVENTIONS: Cats were randomized to receive either prazosin (0.25 mg/cat PO q 12 h, n = 27) or placebo (n = 20) for 1 month following UO. MEASUREMENTS AND MAIN RESULTS: Cats were monitored for rUO, severity of lower urinary tract signs, and medication adverse effects during hospitalization and through weekly conversations with the owner during the 1- month study period and once more at 6 months following discharge. There was no difference in the rUO rate among cats that received prazosin or placebo prior to hospital discharge (2/26 (7%) versus 1/19 (5%), P = 1.00), during the 1- month medication period (4/26 (15%) versus 3/18 (17%), P = 0.776), or at 6 months following treatment for UO (7/19 (37%) versus 4/13 (31%), P = 0.811). There was no difference in the severity of lower urinary tract signs reported by the owners at the 1-, 2-, 3-, or 4-week follow-up periods among the cats in either group (P = 0.62, 0.68, 0.33, 1.00, respectively). Reported adverse effects from prazosin administration included lethargy, ptyalism, diarrhea, anorexia, and malodorous stool. CONCLUSIONS: Although our study results failed to find a difference in the incidence of rUO and severity of lower urinary tract signs among cats receiving prazosin and those receiving placebo, these study results should be interpreted cautiously as our study was underpowered to identify such differences. Larger placebo-controlled, prospective studies are needed to determine the clinical utility of prazosin in prevention of rUO.

Effect of Doxazosin on Autonomic Nervous Control and Urodynamics of Rat Urinary Bladder during Modeled Infravesical Obstruction.

The therapeutic effect of doxazosin (40 µg/kg/day over one month) on urinary bladder was examined in female rats with modeled chronic infravesical obstruction (IVO) produced by graduated mechanical constriction of the proximal urethral segment. In one month, IVO induced a pronounced vesical hypertrophy both in treated and untreated rats that manifested in increased bladder weight and capacity, the latter increment being pronouncedly greater in treated rats. In untreated IVO rats, infusion cystometry revealed elevated basal intravesical pressure of void bladder P0, markedly increased maximal (premicturitional) pressure Pmax, and increased amplitude of spontaneous oscillations of intravesical pressure ΔPdet in filled bladder. Doxazosin produced no significant effect on Pmax rise during IVO, but prevented elevation of P0 and increment of ΔPdet in filled bladder. During gradual filling of urinary bladder in control (intact) rats, the parasympathetic vesical influences increased progressively, while in untreated IVO rats, the adrenergic influences prevailed even at maximal filling of the bladder. In IVO rats, doxazosin prevented the bias of the sympathetic-parasympathetic balance in the filled bladder in favor of sympathetic influences, but did not prevent this bias in a void bladder. It is hypothesized that α-adrenoblockers improve micturition during IVO caused by benign prostatic hyperplasia not only by decreasing the urethral resistance to urine flow due to down-regulation of prostate smooth muscle tone, but also by a direct action of these blockers on detrusor adrenergic receptors and central structures involved in urinary bladder control.

Effect of Selective Prostaglandin E2 EP2 Receptor Agonist CP-533,536 on Voiding Efficiency in Rats with Midodrine-Induced Functional Urethral Obstruction.

OBJECTIVES: We investigated the effect of the selective prostaglandin E2 EP2 receptor agonist CP-533,536 on voiding efficiency in rats with midodrine-induced functional urethral obstruction. METHODS: The effect of CP-533,536 (0.03-0.3 mg/kg, intravenous [i.v.]) on urethral perfusion pressure (UPP) was investigated in anesthetized rats pre-treated with midodrine (1 mg/kg, i.v.), which forms an active metabolite that acts as an α1 -adrenoceptor agonist. The effect of CP-533,536 (0.03-0.3 mg/kg, i.v.) on cystometric parameters was also investigated in anesthetized rats. In addition, the effect of CP-533,536 (0.03-0.3 mg/kg, i.v.) on residual urine volume (RV) and voiding efficiency (VE) was investigated in conscious rats treated with midodrine (1 mg/kg, i.v.). RESULTS: CP-533,536 dose-dependently decreased UPP elevated by midodrine in anesthetized rats. In contrast, CP-533,536 did not affect maximum voiding pressure, intercontraction interval, or intravesical threshold pressure. In conscious rats, midodrine (1 mg/kg, i.v.) markedly increased RV and reduced VE. CP-533,536 dose-dependently ameliorated increases in RV and decreases in VE induced by midodrine. CONCLUSIONS: These results suggest that a selective EP2 receptor agonist could ameliorate the elevation of RV and improve the reduction of VE in rats with functional urethral obstruction caused by stimulation of α1 -adrenoceptors. The mechanism of action might be not potentiation of bladder contraction but rather preferential relief of urethral constriction.

Evaluation of meloxicam for the treatment of obstructive feline idiopathic cystitis.

Objectives The aim of the study was to investigate the effect of the non-steroidal anti-inflammatory drug meloxicam on the clinical course of obstructive idiopathic cystitis in cats in a placebo-controlled clinical study. Methods Thirty-seven cats with obstructive idiopathic cystitis were enrolled. Cats received supportive treatment and an indwelling transurethral catheter for 48 h. On days 0 and 1, all cats received buprenorphine 0.01 mg/kg subcutaneously every 8 h. On day 1, cats were randomly assigned to the meloxicam (n = 18) or placebo group (n = 19) and received meloxicam (0.1 mg/kg on day 1, 0.05 mg/kg on days 2-5) or placebo orally for five consecutive days. Cats were monitored by repeated physical examinations and urinalysis, and with a 5 day questionnaire filled in by the owners after discharge and a telephone interview 3 months after presentation. Parameters for evaluation of treatment success were the occurrence of recurrent urethral obstruction, results of physical examinations and questionnaires. Results Recurrent urethral obstruction occurred in 4/18 cats (22%) in the meloxicam group and 5/19 cats (26%) in the placebo group ( P = 1.000). General demeanour and pain on abdominal palpation during hospitalisation improved significantly in both groups ( P <0.001). After discharge, with regard to general demeanour, food intake and voiding behaviour, there were no significant differences within or between groups at different time points. Conclusions and relevance Orally administered meloxicam for 5 days did not influence the incidence of recurrent urethral obstruction and the recovery from clinical signs in cats with obstructive feline idiopathic cystitis. The persistence of clinical signs in most of the cats 1 week after initial presentation indicates that symptomatic treatment for a longer period of time is warranted.

Standards of care for feline urethral catheters in the UK.

OBJECTIVES: This study aimed to determine the standards of care for urethral catheters (UCs) placed in male cats for treatment of urethral obstruction (UO). It also assessed whether these standards were influenced by year of graduation of the veterinary surgeon (VS). METHODS: One hundred veterinary practices were randomly selected, and a telephone survey was conducted with a VS in the practice. Regarding the last urethral catheterisation performed for a male cat with UO, the VS was asked about the use of antibiotics while the catheter was in situ, whether a closed urinary collection system was used, whether aseptic skin preparation of the patient was performed and whether aseptic hand preparation was performed. A χ(2) test was used to determine whether there were significant differences in these percentages when considering year of graduation. RESULTS: Twenty-seven percent of VSs did not use antibiotics while the urethral catheter was in place, 44% used closed urinary collection systems, 41% performed aseptic skin preparation of the patient and 60% aseptically prepared their hands and wore sterile gloves. There was a statistically significant (P <0.01) difference in antibiotic usage, closed collection system usage and aseptic hand preparation across graduation year groups. CONCLUSIONS AND RELEVANCE: Non-sterile urethral catheter placement with open urinary drainage and antibiotic prophylaxis is still a widespread practice among VSs; however, more recent graduates are more likely to perform the procedure aseptically with a closed urinary collection system and withholding of antibiotics. There is a need for further education for postgraduate veterinarians in the prevention of catheter-associated urinary tract infections in cats and further research to provide evidence-based guidelines for feline urethral catheter care.

Efficacy of intravesical pentosan polysulfate sodium in cats with obstructive feline idiopathic cystitis.

OBJECTIVES: Obstructive feline idiopathic cystitis is a common emergency in small animal practice. There is evidence for a defective glycosaminoglycan layer in the urinary bladder of affected cats. The aim of this study was to investigate the effect of intravesical pentosan polysulfate sodium (PPS) in cats with obstructive feline idiopathic cystitis in a randomised, placebo-controlled, blinded clinical study. METHODS: Thirty-five cats with obstructive feline idiopathic cystitis were enrolled into the study. On day 0, cats were randomised to receive either 30 mg PPS in saline (18 cats) or saline alone as placebo (17 cats) at the time of indwelling urinary catheter placement and then after 24 and 48 h. The catheter was clamped for 30 mins after administration before connecting it to a sterile urine collection system. The procedure was repeated after 24 and 48 h, and then the indwelling catheter was removed. Treatment success was assessed via the incidence of recurrent urethral obstruction, results of a scoring system for physical examination and daily urinalysis from day 0 to 5. RESULTS: Recurrent urethral obstruction occurred in 3/18 cats of the verum group and 3/17 of the placebo group (P = 1.000). The verum group showed a significantly lower degree of microscopic haematuria between day 5 and day 0 (P ⩽0.05). The placebo group showed a significantly lower degree of dipstick haematuria between day 5 and day 0 (P ⩽0.05). There was no difference in the clinical score between the groups in the investigated time period. CONCLUSIONS AND RELEVANCE: Intravesical instillation of PPS three times within 48 h in the chosen dose had no influence on the incidence of recurrent urethral obstruction and clinical signs in cats with obstructive feline idiopathic cystitis.

Reduction of obstruction related bladder overactivity by the guanylyl cyclase modulators BAY 41-2272 and BAY 60-2770 alone or in combination with a phosphodiesterase type 5 inhibitor.

AIMS: To assess the urodynamic effects of soluble guanylyl cyclase (sGC) stimulator, BAY 41-2272, and activator, BAY 60-2770, (which both are able to induce cGMP synthesis even in the absence of nitric oxide (NO)) alone or in combination with a phosphodiesterase type 5 (PDE5) inhibitor, vardenafil, in a model of partial urethral obstruction (PUO) induced bladder overactivity (BO). METHODS: Fifty-six male Sprague-Dawley rats were used, 31 of them underwent PUO. Fourteen rats were used for Western blots to assess PDE5 and sGC expression. For drug evaluation cystometry without anesthesia was performed three days following bladder catheterization. RESULTS: Obstructed rats showed higher micturition frequency and bladder pressures than non-obstructed animals (Intermicturition Interval, IMI, 2.28 ± 0.55 vs. 3.60 ± 0.60 min (± standard deviation, SD); maximum micturition pressure, MMP, 70.1 ± 8.0 vs. 48.8 ± 7.2 cmH2O; both P < 0.05). In obstructed rats vardenafil, BAY 41-2272, and BAY 60-2770 increased IMI (2.77 ± 1.12, 2.62 ± 0.52, and 3.22 ± 1.04 min; all P < 0.05) and decreased MMP (54.4 ± 2.8, 61.5 ± 11.3, and 51.2 ± 6.3 cmH2O; all P < 0.05). When vardenafil was given following BAY 41-2272 or BAY 60-2770 no further urodynamic effects were observed. PDE5 as well as sGC protein expression was reduced in obstructed bladder tissue. CONCLUSIONS: Targeting sGC via stimulators or activators, which increase the levels of cGMP independent of endogenous NO, is as effective as vardenafil to reduce urodynamic signs of BO. Targeting the NO/cGMP pathway via compounds acting on sGC might become a new approach to treat BO.

Intravesical glycosaminoglycans for obstructive feline idiopathic cystitis: a pilot study.

Feline idiopathic cystitis is a common condition, often resulting in repeated episodes of life-threatening urethral obstruction. Defective urinary bladder glycosaminoglycans have been implicated as a causal factor. In this report, a commercially available glycosaminoglycan product was infused into the urinary bladders of cats with urethral obstruction from idiopathic cystitis to study the effect on repeated obstruction. In this randomized, blind, placebo-controlled clinical trial, the therapeutic protocol was well tolerated with no adverse effects. Whereas no glycosaminoglycan-treated cats (n = 9) developed repeated urethral obstruction during the 7 day follow-up period, 3/7 placebo-treated cats developed repeated obstructions. Approaching statistical significance (P = 0.06), these data suggest that further investigation of this new treatment option is warranted.

[Effect of coicis semen oil on renal interstitial fibrosis in rats with unilateral urethral obstruction].

OBJECTIVE: To study the effect and mechanism of Coicis Semen oil (Kanglaite injection, KLT) on renal interstitial fibrosis induced by unilateral ureteral obstruction (UUO). METHOD: Fifty-four male SD rats were randomly divided into 3 groups, 6 in each group, the sham operated group, the model group, and the KLT group. Renal interstitial fibrosis model was established in rats by UUO. After administration of KLT (15 mL x kg(-1) x d(-1)) for 3, 7 and 14 days, the dynamic histological changes of renal interstitial tissues were observed and renal damage including tubular impairment and interstitial fibrosis were quantified on HE and Masson stained tissue sections. The expression of alpha-smooth muscle actin (alpha-SMA) and transforming growth factor-beta1 (TGF-beta1) were measured by immunohistochemistry staining sections. The protein expression of p-Smad2 and Smad7 were detected by Western blot respectively. RESULT: The degree of tubular damage in KLT group was much lower than that in UUO group (P < 0.05). The expression of alpha-SMA and TGF-beta1 was decreased in both UUO group and KLT group, while it was significantly lower in KLT group at every time point. The protein expression of p-Smad2 was obviously decreased while the protein expressions of Smad7 was obviously increased in KLT group, compared with the UUO group (P < 0.05). CONCLUSION: Coicis Semen oil could attenuate the tubulo-interstitial fibrosis, probable by intervening the TGF-beta/Smads signal transduction pathway of UUO rats.

Spinal cord FAAH in normal micturition control and bladder overactivity in awake rats.

PURPOSE: We assessed whether spinal inhibition of the cannabinoid degrading enzyme FAAH would have urodynamic effects in normal rats and rats with bladder overactivity induced by partial urethral obstruction or prostaglandin E2. We also determined the expression of FAAH, and the cannabinoid receptors CB1 and CB2 in the sacral spinal cord. MATERIALS AND METHODS: We used 44 rats for functional (cystometry) and Western blot experiments. The FAAH inhibitor oleoyl ethyl amide (3 to 300 nmol) was administered intrathecally (subarachnoidally) or intravenously. The expression of FAAH and CB1/CB2 receptors was determined by Western blot. RESULTS: Oleoyl ethyl amide given intrathecally affected micturition in normal rats and rats with bladder overactivity but effects were more pronounced in the latter. In normal rats oleoyl ethyl amide only decreased micturition frequency, while it decreased frequency and bladder pressures in rats with bladder overactivity. Intravenous oleoyl ethyl amide (3 to 300 nmol) had no urodynamic effect. FAAH and CB1/CB2 receptors were expressed in the rat sacral spinal cord. The expression of CB1/CB2 receptors but not FAAH was higher in obstructed than in normal rats. CONCLUSIONS: FAAH inhibition in the sacral spinal cord by oleoyl ethyl amide resulted in urodynamic effects in normal rats and rats with bladder overactivity. The spinal endocannabinoid system may be involved in normal micturition control and it appears altered when there is bladder overactivity.

Intravesical application of lidocaine and sodium bicarbonate in the treatment of obstructive idiopathic lower urinary tract disease in cats.

BACKGROUND: In human patients with interstitial cystitis, intravesical instillation of alkalinized lidocaine sometimes is associated with sustained amelioration of symptoms beyond the acute treatment phase. Interstitial cystitis shares many features in common with feline idiopathic cystitis. OBJECTIVE: To evaluate whether intravesical instillation of alkalinized lidocaine decreases recurrence of urethral obstruction and severity of clinical signs in cats with obstructive idiopathic LUTD. ANIMALS: Twenty-six cats with obstructive idiopathic LUTD. Twelve cats in case group (treatment with alkalinized lidocaine) and 14 control cats (treatment with placebo or standard treatment). METHODS: Cats were randomly assigned to treatment (2 or 4 mg/kg lidocaine and sodium bicarbonate) or placebo groups (0.2 mL/kg saline solution and sodium bicarbonate). The intravesical instillation was done once a day for 3 days. Some cats underwent standard treatment only (indwelling urinary catheter for 3 days without intravesical instillations). A 2-week, 1-month, and 2-month follow-up after treatment was made using a questionnaire. The recurrence rate and amelioration scores of clinical signs were assessed and compared. RESULTS: Recurrence of urethral obstruction was 58% (7/12) in the case group and 57% (8/14) in the control group. Amelioration scores were similar between the 2 groups. CONCLUSION AND CLINICAL IMPORTANCE: Intravesical administration of lidocaine for up to 3 consecutive days had no apparent beneficial effect on decreasing recurrence rate and severity of clinical signs in cats with obstructive idiopathic LUTD.

Beta3-adrenoceptors in the rat sacral spinal cord and their functional relevance in micturition under normal conditions and in a model of partial urethral obstruction.

AIMS: Beta3-adrenoceptor selective agonists are evaluated as a new treatment for patients with lower urinary tract symptoms . It is believed that ß3-AR selective agonists exert their effects via a peripheral site of action. However, ß3-ARs have been found in brain tissue. This study examined whether ß3-ARs are present in rat sacral spinal cord, and whether there are differences in ß3-AR expression between normal and partial urethral obstruction (PUO) animals, and furthermore assessed the functional relevance of spinal ß3-ARs for micturition. METHODS: Thirty-eight male Sprague-Dawley rats underwent either PUO or sham-operation. Two weeks after operation, half of the animals were used for histomorphological analysis. Remaining animals were used for functional experiments, where a ß3-AR selective agonist, BRL 37344, was given intrathecally. Bladder function was assessed by continuous cystometry in non-anesthetized animals before and after drug administration. RESULTS: Beta3-ARs were found in sacral spinal cord segments with an accumulation in the ventral horn. There was a significant increase of ß3-AR expression in obstructed rats. In functional experiments obstructed rats showed increased bladder weight, micturition frequency, spontaneous activity, and bladder pressures (all P < 0.05) compared to controls. Intrathecally administered BRL 37344 showed no effect in non-obstructed rats. In obstructed rats intrathecal BRL 37344 significantly reduced bladder pressures, spontaneous activity, and micturition frequency (all P < 0.05). CONCLUSIONS: Beta3-ARs are present in rat sacral spinal cord, and are significantly up-regulated after PUO. Besides their well-established peripheral site of action in the treatment of voiding dysfunction, ß3-AR selective agonists might exert relevant effects at a central nervous site of action.

Cannabinor, a selective cannabinoid-2 receptor agonist, improves bladder emptying in rats with partial urethral obstruction.

PURPOSE: We studied the effects of chronic treatment with the novel selective cannabinoid 2 receptor agonist cannabinor (Procter & Gamble Pharmaceuticals, Cincinnati, Ohio) on bladder function in conscious rats with partial urethral obstruction and on the functional properties of isolated detrusor muscle. MATERIALS AND METHODS: A total of 24 female Sprague-Dawley® rats with surgically created partial urethral obstruction received daily intraperitoneal injections of 3 mg/kg cannabinor (12) or saline as controls (12) for 2 weeks. Cystometry was done, the rats were sacrificed and the bladders were prepared for in vitro studies. RESULTS: Mean ± SEM bladder weight was 0.97 ± 0.15 gm in controls and 0.53 ± 0.08 gm in cannabinor treated rats (p <0.05). There was no difference between the groups in the mean micturition interval, or mean baseline, threshold, flow or maximum pressure. In controls and cannabinor treated rats mean post-void residual volume was 0.28 ± 0.07 and 0.06 ± 0.02 ml, mean micturition compliance was 0.032 ± 0.006 and 0.069 ± 0.016 ml/cm H(2)O, and mean bladder wall force at the start of flow was 950 ± 280 and 1,647 ± 325 mN/gm, respectively (each p <0.05). Nonvoiding contractions were significantly less frequent in cannabinor treated rats than in controls. We noted no difference in carbachol (Sigma®) half maximum concentration between the groups but the carbachol maximum response in detrusor strips from cannabinor treated rats was significantly higher than that in control strips. CONCLUSIONS: In rats with partial urethral obstruction treated daily for 14 days with cannabinor bladder weight was lower, the ability to empty the bladder was preserved and nonvoiding contraction frequency was low compared to those in controls. Detrusor preparations from cannabinor treated rats showed a higher response to nerve stimulation than those from controls. Selective cannabinoid 2 receptor activation may be a novel principle to enable improved bladder function after partial urethral obstruction.

Urodynamic evaluation of fesoterodine metabolite, doxazosin and their combination in a rat model of partial urethral obstruction.

OBJECTIVE: To evaluate the urodynamic effects of fesoterodine, a new antimuscarinic agent, alone and combined with doxazosin, in a rat model of partial urethral obstruction (PUO), as 35-83% of men with bladder outlet obstruction (BOO) secondary to benign prostatic hyperplasia (BPH) have overactive bladder (OAB) syndrome, and as the combination of alpha(1)-adrenoceptor- and muscarinic-receptor antagonists has been proposed to be beneficial for these patients. MATERIALS AND METHODS: Thirty-seven male Sprague-Dawley rats (250 g) had surgically induced PUO; 2 weeks later they were evaluated by cystometry with no anaesthesia or any restraint. After a 1-h period either 5-hydroxymethyl tolterodine (5-HMT, the active metabolite of fesoterodine, previously known as SPM 7605), doxazosin or a combination of both, was given intravenously (0.1 mg/kg body weight), and cystometry was continued for another 45 min. Fifteen healthy, age-matched rats served as a control. RESULTS: At 2 weeks after surgery the obstructed rats had an greater bladder weight, threshold pressure (TP) and micturition frequency (MF), and lower bladder capacity (BCap) and micturition volume (MV) than the controls. 5-HMT did not cause urinary retention in obstructed rats, but decreased TP, maximum pressure (MP), spontaneous bladder activity (SA) and, paradoxically, increased MF. Doxazosin alone decreased TP, MP, MF and increased BCap and MV. 5-HMT and doxazosin together did not depress the ability to empty the bladder, and showed decreased TP, MP and SA. CONCLUSIONS: 5-HMT, alone and in combination, did not impair the voiding ability in obstructed rats. Doxazosin counteracted some of the 'negative' effects of 5-HMT in this model (increase of MF) and did not attenuate the 'positive' effects (decrease of bladder SA). In this model, the combination of 5-HMT and doxazosin appeared to be urodynamically safe and well tolerated.

Vardenafil-induced relaxation and cyclic nucleotide levels in normal and obstructed rat urinary bladder.

OBJECTIVE: To study the effects of the phosphodiesterase-5 inhibitor, vardenafil, on contraction and cyclic nucleotide levels in isolated detrusor preparations with and without mucosa, from control rats and rats with partial urethral obstruction (PUO) and intact mucosa. MATERIALS AND METHODS: Female Sprague-Dawley rats were divided into groups subjected to PUO for 14 days (six), and sham-operated control rats (12). Detrusor preparations were mounted in organ baths and effects of increasing concentrations of vardenafil (1 nm to 100 microm) assessed on carbachol-activated (1 microm) preparations, and on contractions induced by transmural activation of nerves (electrical field stimulation, EFS). Levels of cGMP and cAMP were determined using radioimmunoassays. RESULTS: Vardenafil caused concentration-dependent relaxations of carbachol-contracted detrusor, the mean (sd) of which at 100 microm was 91 (4)% in control and 100% in PUO rats. The -log 50% inhibitory concentration (IC(50)) was 4.41 (0.08) and 4.73 (0.05) (P < 0.01), respectively. Removing the mucosa increased the relaxant effect of vardenafil at 1-10 microm (P < 0.05) although -log IC(50) values were unaffected compared to the control. The cGMP levels ( pmol/mg protein) in control preparations increased from 2.5 (0.6) to 5.0 (0.8), and from 1.4 (0.2) to 7.2 (1.3) in obstructed bladders. In mucosa-denuded preparations the cGMP content increased from 0.6 (0.1) to 1.6 (0.4) in response to vardenafil. In control rats, the levels of cAMP increased from 12.8 (2.5) to 18.9 (0.9) (P < 0.05) after vardenafil. In mucosa-denuded preparations the cAMP levels after vardenafil increased from 16.5 (2.11) to 37.8 (3.4) (P < 0.01). In PUO bladders, the tissue content of cAMP increased from 12.6 (2.4) to 20.6 (3.4) (P < 0.01). Vardenafil concentration-dependently inhibited nerve-induced contractions in all groups studied. At 100 microm 19 (3)% of the control contraction remained, vs 8 (1)% for preparations from obstructed rats, and 11 (4)% in mucosa-denuded preparations. CONCLUSION: In normal rats, vardenafil relaxed carbachol- and inhibited EFS-induced contractions of detrusor preparations with and without urothelium, and in PUO rats with urothelium. Relaxations were accompanied by increases in both cAMP and cGMP content. It is proposed that vardenafil-induced relaxation of rat detrusor, also in obstructed and mucosa-denuded preparations, is mediated via cAMP.

Use of Walpole's solution for treatment of goats with urolithiasis: 25 cases (2001-2006).

OBJECTIVE: To determine results of ultrasound-guided cystocentesis and percutaneous infusion of Walpole's solution for treatment of male goats with urolithiasis. DESIGN: Retrospective case series. ANIMALS: 25 male goats with urolithiasis treated with Walpole's solution. PROCEDURES: Information obtained from the medical records included signalment, degree of urethral obstruction (partial vs complete), pertinent examination findings, concurrent illnesses, diet, other treatments administered, duration of hospitalization, whether the obstruction resolved, and outcome (ie, discharged vs euthanized). RESULTS: 14 (58%) animals had complete urethral obstruction, and 10 (42%) had partial obstruction (degree of urethral patency was not recorded in 1 animal). Walpole's solution was infused once in 18 (72%) animals, twice in 6 (24%) animals, and 3 times in 1 (4%) animal. The amount of Walpole's solution required to achieve the target urine pH of 4 to 5 ranged from 50 to 250 mL. In 20 (80%) goats, the urethral obstruction resolved, and the goat was discharged. The remaining 5 (20%) goats were euthanized because of unresolved urethral obstruction. Six of the 20 (30%) goats that were discharged were reexamined because of recurrence of urethral obstruction. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that ultrasound-guided cystocentesis in combination with percutaneous infusion of Walpole's solution may be a useful treatment in male goats with obstructive urolithiasis.