FGF2-mediated reciprocal tumor cell-endothelial cell interplay contributes to the growth of chemoresistant cells: a potential mechanism for superficial bladder cancer recurrence.

Patients with superficial bladder cancer can be definitively cured by one single transurethral resection (TUR) with additional intravesical chemotherapy; however, up to 75 % of cases display frequent and multiple recurrences. One of the major causes of recurrence is that chemotherapeutic drugs used in intravesical regimens may induce chemoresistance. However, the mechanisms by which these chemoresistant cells develop into recurrent tumors remain unclear. Recent clinical evidence revealed that the expression of pro-angiogenic factor FGF2 was associated with early local relapse in patients with superficial bladder cancer. In this study, we conducted a preliminary investigation of the mechanisms of chemoresistant cells mediated bladder cancer recurrence, focusing on FGF2-initiated tumor cell-endothelial cell interaction on chemoresistant cancer cell growth. We found that the expression of FGF2 was increased in chemoresistant bladder cell lines and in bladder tissues after intravesical chemotherapy. Although chemoresistant bladder cells grow slower than parental cells, chemoresistant bladder cancer cells had stronger ability than parental cells to stimulate endothelial cell migration, growth, and tube formation by producing FGF2. Inversely, endothelial cells significantly promoted chemoresistant bladder cancer growth in vitro and in vivo. Thus, targeting chemotherapy-induced FGF2 upregulation may provide a promising approach to manage the recurrence of superficial bladder cancer.

Kaempferol suppresses bladder cancer tumor growth by inhibiting cell proliferation and inducing apoptosis.

The effects of the flavonoid compound, kaempferol, which is an inhibitor of cancer cell proliferation and an inducer of cell apoptosis have been shown in various cancers, including lung, pancreatic, and ovarian, but its effect has never been studied in bladder cancer. Here, we investigated the effects of kaempferol on bladder cancer using multiple in vitro cell lines and in vivo mice studies. The MTT assay results on various bladder cancer cell lines showed that kaempferol enhanced bladder cancer cell cytotoxicity. In contrast, when analyzed by the flow cytometric analysis, DNA ladder experiment, and TUNEL assay, kaempferol significantly was shown to induce apoptosis and cell cycle arrest. These in vitro results were confirmed in in vivo mice studies using subcutaneous xenografted mouse models. Consistent with the in vitro results, we found that treating mice with kaempferol significant suppression in tumor growth compared to the control group mice. Tumor tissue staining results showed decreased expressions of the growth related markers, yet increased expressions in apoptosis markers in the kaempferol treated group mice tissues compared to the control group mice. In addition, our in vitro and in vivo data showed kaempferol can also inhibit bladder cancer invasion and metastasis. Further mechanism dissection studies showed that significant down-regulation of the c-Met/p38 signaling pathway is responsible for the kaempferol mediated cell proliferation inhibition. All these findings suggest kaempferol might be an effective and novel chemotherapeutic drug to apply for the future therapeutic agent to combat bladder cancer.

Curcumin promotes KLF5 proteasome degradation through downregulating YAP/TAZ in bladder cancer cells.

KLF5 (Krüppel-like factor 5) plays critical roles in normal and cancer cell proliferation through modulating cell cycle progression. In this study, we demonstrated that curcumin targeted KLF5 by promoting its proteasome degradation, but not by inhibiting its transcription in bladder cancer cells. We also demonstrated that lentivirus-based knockdown of KLF5 inhibited cancer cell growth, while over-expression of a Flag-tagged KLF5 could partially reverse the effects of curcumin on cell growth and cyclin D1 expression. Furthermore, we found that curcumin could down-regulate the expression of Hippo pathway effectors, YAP and TAZ, which have been reported to protect KLF5 protein from degradation. Indeed, knockdown of YAP by small interfering RNA caused the attenuation of KLF5 protein, but not KLF5 mRNA, which was reversed by co-incubation with proteasome inhibitor. A xenograft assay in nude mice finally proved the potent inhibitory effects of curcumin on tumor growth and the pro-proliferative YAP/TAZ/KLF5/cyclin D1 axis. Thus, our data indicates that curcumin promotes KLF5 proteasome-dependent degradation through targeting YAP/TAZ in bladder cancer cells and also suggests the therapeutic potential of curcumin in the treatment of bladder cancer.

Sinomenine reverses multidrug resistance in bladder cancer cells via P-glycoprotein-dependent and independent manners.

P-Glycoprotein-mediated multidrug resistance is a frequent event during chemotherapy and a key obstacle for bladder cancer therapy. Search for strategies to reverse multidrug resistance is a promising approach to improve the management of bladder cancer. In the present study, we reported a novel P-glycoprotein-mediated multidrug resistant cell model 253J/DOX, which was generated from human bladder cancer 253J cell line. Furthermore, we found that the multidrug resistant phenotype of 253J/DOX cells could be overcome by sinomenine, an alkaloid derived from the stem of Sinomenium acutum. Mechanistically, the chemosensitive effect by sinomenine was mediated by down-regulating P-glycoprotein expression, as well as triggering apoptotic pathways. The chemosensitive effect of sinomenine may make it a prime candidate agent to target bladder cancer.

Increased PrLZ-mediated androgen receptor transactivation promotes prostate cancer growth at castration-resistant stage.

Most advanced prostate cancers (PCa) will develop into the castration-resistant stage following androgen deprivation therapy, yet the molecular mechanisms remain unclear. In this study, we found PrLZ, a newly identified Prostate Leucine Zipper gene that is highly expressed in PCa could interact with the androgen receptor (AR) directly leading to enhance AR transactivation in the castration-resistant condition. PrLZ might enhance AR transactivation via a change of AR conformation that leads to promotion of AR nuclear translocation and suppression of AR degradation via modulating the proteasome pathway, which resulted in increased prostate-specific antigen expression and promoted PCa growth at the castration-resistant stage. Clinical PCa sample survey from same-patient paired specimens found increased PrLZ expression in castration-resistant PCa following the classical androgen deprivation therapy. Targeting the AR-PrLZ complex via ASC-J9® or PrLZ-siRNA resulted in suppression of PCa growth in various human PCa cells and in vivo mouse PCa models. Together, these data not only strengthen PrLZ roles in the transition from androgen dependence to androgen independence during the castration-resistant stage, but they may also provide a new potential therapy to battle PCa at the castration-resistant stage.

Holmium laser enucleation of the prostate: a modified enucleation technique and initial results.

PURPOSE: Although holmium laser enucleation of the prostate has been proven to be an excellent technique for the treatment of benign prostatic hyperplasia, it has not been widely applied due to technical difficulties and longer operative time. We modified the current technique of enucleation and present our initial experience. MATERIALS AND METHODS: A total of 189 patients with benign prostatic hyperplasia underwent prostatectomy with our modified technique for holmium laser enucleation of the prostate. Intraoperative and postoperative data were prospectively collected. For followup International Prostate Symptom Score, quality of life, maximal flow rate and post-void residual urine were recorded. RESULTS: Mean±SD preoperative prostate volume was 78.1±24.3 cc and 60.9±39.2 gm tissue were enucleated. Mean operative and enucleation times were 54.7±21.1 and 36.5±16.3 minutes, respectively. Mean serum hemoglobin decrease was 0.98±0.72 gm/dl. Mean catheter time was 1.2±0.5 days and mean postoperative hospital stay was 4.9±3.4 days. Serious complications were not observed. Three patients complained of transient stress incontinence which resolved within 3 months. Significant improvement occurred in International Prostate Symptom Score, quality of life, maximal flow rate and post-void residual urine volume at 3 and 6-month followup compared with the preoperative baseline. CONCLUSIONS: The modified holmium laser enucleation of the prostate technique is effective and safe when treating benign prostatic hyperplasia.

Twist confers chemoresistance to anthracyclines in bladder cancer through upregulating P-glycoprotein.

BACKGROUND: The membrane transporter P-glycoprotein (P-gp) was found to mediate chemoresistance, which is one of the obstacles to effective chemotherapy in several types of human cancer. The transcription factor Twist, which has been reported to participate in cancer invasion and metastasis, also plays a vital role in the progression of chemoresistance. However, the effect of Twist on P-gp-related chemoresistance remains dubious. METHODS AND RESULTS: We found that Twist can regulate the expression of P-gp and then confer resistance to anthracycline drugs in human bladder cancer cells. Firstly, Twist was found to be coexpressed with P-gp in human bladder cancer cells and tissues, which were associated with enhanced chemoresistance to anthracycline drugs. Secondly, knockdown of Twist by specific siRNA treatment significantly sensitized bladder cancer cells to anthracycline drugs via inhibiting P-gp expression. Bladder cancer cells that survived transient exposure to anthracycline drugs showed higher levels of P-gp expression and more nuclear localization of Twist than untreated cells. CONCLUSION: We report a novel mechanism of anthracycline chemoresistance in bladder cancer in which activated Twist mediates P-gp expression in addition to its antiapoptotic roles. Therapeutic strategies targeting Twist may improve the management of recurrent bladder cancer after chemotherapy.

Characterization of smooth muscle differentiation of purified human skeletal muscle-derived cells.

The purpose of this study is to characterize the smooth muscle differentiation of purified human muscle-derived cells (hMDCs). The isolation and purification of hMDCs were conducted by modified preplate technique and Dynal CD34 cell selection. Smooth muscle cell differentiation was induced by the use of smooth muscle induction medium (SMIM) and low-serum medium. The gene expressions at the mRNA and protein levels of undifferentiated and differentiated hMDCs were tested by RT-PCR, Western blot and immunofluorescence studies. Western blot and immunofluorescence studies demonstrated the purified hMDCs cultured in SMIM for 4 weeks and expressed significant amount of smooth muscle myosin heavy chain (MHC) and α-smooth muscle actin (ASMA). The cells cultured in low-serum medium for 4 weeks also expressed ASMA, while the control group did not. RT-PCR analysis showed increased gene expression of smooth muscle markers, such as ASMA, Calponin, SM22, Caldesmon, Smoothelin and MHC when purified hMDCs were exposed to SMIM for 2 and 4 weeks when compared to the controls. In conclusion, we confirmed the smooth muscle differentiation capability of purified hMDCs. The gene expression of smooth muscle differentiation of purified hMDCs was characterized. These cells may be potential biomaterials for human tissue regeneration.

Specific survivin dual fluorescence resonance energy transfer molecular beacons for detection of human bladder cancer cells.

AIM: Survivin molecular beacons can be used to detect bladder cancer cells in urine samples non-invasively. The aim of this study is to improve the specificity of detection of bladder cancer cells using survivin dual fluorescence resonance energy transfer molecular beacons (FRET MBs) that have fluorophores forming one donor-acceptor pair. METHODS: Survivin-targeting dual fluorescence resonance energy transfer molecular beacons with unique target sequences were designed, which had no overlap with the other genes in the apoptosis inhibitor protein family. Human bladder cancer cell lines 5637, 253J and T24, as well as the exfoliated cells in the urine of healthy adults and patients with bladder cancer were examined. Images of cells were taken using a laser scanning confocal fluorescence microscope. For assays using dual FRET MBs, the excitation wavelength was 488 nm, and the emission detection wavelengths were 520±20 nm and 560±20 nm, respectively. RESULTS: The human bladder cancer cell lines and exfoliated cells in the urine of patients with bladder cancer incubated with the survivin dual FRET MBs exhibited strong fluorescence signals. In contrast, no fluorescence was detected in the survivin-negative human dermal fibroblasts-adult (HDF-a) cells or exfoliated cells in the urine of healthy adults incubated with the survivin dual FRET MBs. CONCLUSION: The results suggest that the survivin dual FRET MBs may be used as a specific and non-invasive method for early detection and follow-up of patients with bladder cancer.

MUC15 loss facilitates epithelial-mesenchymal transition and cancer stemness for prostate cancer metastasis through GSK3ß/ß-catenin signaling.

Patients with prostate cancer (PCa) have a high incidence of relapse and metastasis. Unfortunately, the molecular mechanisms underlying these processes have not been fully elucidated. In our study, we demonstrate that MUC15, a member of the mucin family, is a novel tumor suppressor in PCa that modulates epithelial-mesenchymal transition (EMT) and cancer stemness, contributing to PCa metastasis. First, MUC15 expression was found to be decreased in PCa tissues compared with para-carcinoma tissues. Moreover, we observed that MUC15 suppressed cell migration and invasion, both in vitro and in vivo, but had no effect on cell proliferation. Mechanistically, knockdown of MUC15 increased GSK3ß phosphorylation and promoted ß-catenin nuclear translocation. Therefore, the ß-catenin-specific inhibitors XAV939 and PRI-724 rescued EMT in MUC15-deficient cell lines. Taken together, these results indicate that MUC15 is downregulated in PCa tissues and serves as a potential target to prevent PCa metastasis, which can inhibit EMT and cancer stemness via the GSK3ß/ß-catenin signaling pathway.

Purification of human muscle-derived cells using an immunoselective method for potential use in urological regeneration.

OBJECTIVE: To purify human muscle-derived cells (hMDCs) that could be used for managing urinary incontinence, erectile dysfunction and for bladder reconstitution. MATERIALS AND METHODS: hMDCs isolated by a modified preplate technique (MPT) from skeletal muscles of limbs were purified by CD34 antibody and magnetic Dynabeads cell selection system (MDCSS). The growth-doubling time of the hMDCs and purified hMDCs was measured. The purified hMDCs were characterized by flow cytometry, immunofluorescence and confocal laser scanning microscopy. RESULTS: The growth-doubling time of hMDCs was approximately 24 h, which increased to 35 h after purifying using the MDCSS. There were scanty fibroblasts after purification and the MDCSS-purified hMDCs were identified by high expression of stem cell markers and myoblast markers. The expression proportion of the stem cell marker CD34 and myoblast marker CD56 in the hMDCs was higher after purification (MDCSS) than before (MPT), at 32.13% vs 4.12% and 21.56% vs 8.60%, respectively. CONCLUSIONS: The purification of hMDCs showing high expression of stem cell and myoblast markers is feasible. These purified hMDCs could potentially be used for urological regeneration.

A survey of erectile dysfunction in Taiwan: use of the erection hardness score and quality of erection questionnaire.

INTRODUCTION: There are currently no studies in the Asia-Pacific region using the erection hardness score (EHS) and Quality of Erection Questionnaire (QEQ) to assess erectile dysfunction (ED). AIMS: To provide up-to-date data on the prevalence of ED in Taiwanese men and to validate the EHS and QEQ in this population. METHODS: A representative sample of 1,060 men aged ≥ 30 years completed a telephone interview. ED status was confirmed via direct questioning and using the abridged five-item version of the 15-item International Index of Erectile Function (IIEF-5). Responses regarding EHS, QEQ, marital and sexual satisfaction, and attitude to treatment were also recorded. MAIN OUTCOME MEASURES: IIEF, EHS, and QEQ. RESULTS: The prevalence of ED, as defined by IIEF-5, was 27% among all respondents and 29% among those aged ≥ 40 years. Although, the prevalence of ED increased with age, men of all ages tended to underestimate their erectile problems. Among men who indicated that they did not have ED, 25% were found to have mild to moderate ED according to the IIEF-5 assessment. An EHS ≤ 3, indicating the presence of ED, was reported in 26% of men. The EHS was consistent with the QEQ: When the EHS was 4, the satisfaction of each domain of QEQ ranged from 85% to 90%. The QEQ score correlated well with the IIEF-5 score and significantly affected both sexual and marital satisfaction (P < 0.005). CONCLUSIONS: These data indicate that EHS is a simple, practical tool for clinical use. QEQ scores appear to be independently associated with sexual and marital satisfaction, and may be of value in the assessment and monitoring of ED patients. While ED is a common health problem in Taiwan and the prevalence of ED increases with age, affected men lack awareness regarding the presence of erectile problems and the importance of initiating timely and effective treatment.

Correlation between pretreatment serum biochemical markers and treatment outcome for prostatic cancer with bony metastasis.

BACKGROUND: This study was undertaken to evaluate whether or not pretreatment serum biochemical markers are prognostic factors for prostatic cancer with bony metastasis in patients on hormonal treatment. METHODS: Between 1983 and 1998, 127 patients with prostatic cancer and bony metastasis were included for evaluation. Serum prostate-specific antigen, alkaline phosphatase, calcium (Ca), lactic dehydrogenase, inorganic phosphate, gamma-glutamine transpeptidase, uric acid, albumin (Alb), iron, cholesterol (Cho), triglyceride, alanine aminotransferase, aspartate aminotransferase, and hemoglobin (Hb) were checked before treatment. The patients were divided into 2 groups according to their response (group 1, good response; group 2, poor response). RESULTS: There were 54 patients in group 1 and 73 patients in group 2. Pretreatment levels of serum Ca, Alb, Cho and Hb were higher in group 1 than in group 2, while the other parameters were lower in group 1 than in group 2; only pretreatment levels of serum Ca, Alb and Hb were significantly different between groups (p < 0.05). When stratified by tumor grading, patients in group 1 still had significantly higher pretreatment levels of Ca, Alb and Hb than those in group 2. CONCLUSION: Higher pretreatment serum levels of Ca, Alb and Hb are good prognostic factors for patients with metastatic prostatic cancer on hormonal treatment, irrespective of tumor grading.

Correction: Infiltrating mast cells increase prostate cancer chemotherapy and radiotherapy resistances via modulation of p38/p53/p21 and ATM signals.

[This corrects the article DOI: 10.18632/oncotarget.6372.].

Attenuation of oxidative stress after varicocelectomy in subfertile patients with varicocele.

PURPOSE: We examined changes due to oxidative damage to spermatozoa and alterations in antioxidant capacity in subfertile patients with varicocele before and after varicocelectomy in a prospective study. MATERIALS AND METHODS: A total of 30 young subfertile male patients with varicocele were recruited in this study. Varicocele was diagnosed by physical examination and Doppler ultrasound. Semen analysis was performed in the 30 patients before and 6 months after varicocelectomy using a computer assisted semen analyzer. The parameters for evaluating oxidative stress changes were 4977 bp deletion of mitochondrial DNA in sperm, as detected by polymerase chain reaction, the 8-OHdG (8-hydroxy-2'-deoxyguanosine) content in spermatozoa DNA, as measured by a high performance liquid chromatography electrochemical method, and seminal plasma protein thiols and ascorbic acid, as measured by spectrophotometric methods. RESULTS: Semen quality, including motility, morphology and sperm density, was improved in 22 patients (73.3%) after varicocelectomy. The incidence of 4977 bp deletion of mitochondrial DNA in sperm was 40% (12 of 30 patients) and 13.3% (4 of 30) before and after surgery, respectively. Mean +/- SD 8-OHdG content in sperm DNA, and seminal plasma protein thiols and ascorbic acid were 10.27 +/- 2.24/10(5) 2'-deoxyguanosine, 0.77 +/- 0.75 nmole/ml and 1.87 +/- 0.40 mg/dl before operation, and 5.95 +/- 1.46/10(5) 2'-deoxyguanosine, 3.00 +/- 1.17 nmole/ml and 3.12 +/- 0.94 mg/dl after surgery, respectively. The incidence of 4977 bp deletion of mitochondrial DNA in sperm and the level of 8-OHdG in sperm DNA were decreased, and seminal plasma protein thiols and ascorbic acid were increased significantly in all 30 patients after varicocelectomy. Also, in the 8 patients in whom semen quality did not improve after surgery a significant decrease in 8-OHdG in sperm DNA, and a significant increase in seminal plasma protein thiols and ascorbic acid were observed. CONCLUSIONS: Subfertile patients with varicocele had a significant decrease in oxidative damage in sperm DNA and an increase in antioxidant capacity in seminal plasma after varicocelectomy, indicating that surgery is effective treatment in such patients.

Successful use of modified suprapubic catheter to rescue prostatorectal fistula.

Prostatorectal fistula is a complication following radiotherapy. It remains a clinical challenge to treat because most patients experience a poor quality of life. This case report discusses a modified suprapubic catheter for use in a patient with a prostatorectal fistula that developed after radiotherapy for localized prostate cancer. It is an inexpensive, easily available, and more patient-tolerable catheter that improves quality of life. Herein, we describe the development of this catheter.

Prepubertal testicular germ cell tumors: 25-year experience in Taipei Veterans General Hospital.

BACKGROUND: Due to the rarity of testicular tumors in the prepubertal population, adequate information about their biological course is difficult to document well in a single institution. The purpose of this study was to focus on prepubertal males in an attempt to evaluate clinical features and optimal management among various testicular germ cell tumors with long-term follow-up. METHODS: We retrospectively reviewed the records of children younger than 12 years of age with primary testicular germ cell tumors between February 1981 and December 2005 at Taipei Veterans General Hospital. Thirty-four children were diagnosed with adequate clinical and pathologic data. The stage of the disease was determined according to the staging system used by the Children's Oncology Group. Mean follow-up time was 139 months (range, 2-283 months). RESULTS: All of the 34 prepubertal patients were diagnosed initially with a painless scrotal mass. The mean age of the patients at diagnosis ranged from 6 months to 84 months (mean, 20.5 months). All patients underwent radical orchiectomy as an initial treatment. Twenty-nine (85.3%) patients had yolk sac tumors, and 5 (14.7%) had mature teratomas. Of the 29 patients with yolk sac tumor, 26 (89.7%) were diagnosed as stage I, 1 (3.4%) as stage III, and 2 (7.0%) as stage IV. Five (19.2%) of the 26 stage I yolk sac tumors progressed to metastasis after radical orchiectomy, and all of these 5 patients later received chemotherapy. One patient initially with stage III yolk sac tumor and 2 patients with stage IV yolk sac tumor were also treated with chemotherapy. Eventually, 1 patient with stage IV yolk sac tumor died due to tumor progression; the remaining 28 patients with yolk sac tumor all survived without tumor relapse after appropriate treatment. In the 5 patients with teratomas, there was no tumor relapse after radical orchiectomy with a mean follow-up time of 139.1 months. The 5-year survival rates for yolk sac tumor and teratomas were 96.5% and 100%, respectively. CONCLUSION: The most common prepubertal malignant testicular tumor is yolk sac tumor, and the most common benign testicular tumor is teratoma. Children with testicular germ cell tumors have excellent long-term survival rates after appropriate treatment.

The expression and function of RASAL2 in renal cell carcinoma angiogenesis.

Patients with renal cell carcinoma (RCC) often develop resistance to antivascular drugs and eventually succumb to disease. However, the underlying molecular mechanism remains poorly understood. In this study, we demonstrated that RASAL2, a RAS GTPase-activating protein, played a tumor-suppressive role in RCC by targeting tumor angiogenesis. Firstly, we showed that RASAL2 was frequently epigenetically silenced in RCC, and its loss was negatively correlated with overall survival of RCC patients. Furthermore, we discovered that RASAL2 could inhibit RCC angiogenesis in vitro and in vivo. Mechanistically, we identified that RASAL2 could activate GSK3ß by reducing Ser9 phosphorylation and subsequently decrease the expression of c-FOS and vascular endothelial growth factor A (VEGFA). Interruption of the p-GSK3ß/c-FOS pathway with the specific inhibitor or small interfering RNA could reverse the expression of VEGFA, which may provide a new insight to prevent RCC from resistance to antivascular therapy.

RASAL2 inhibits tumor angiogenesis via p-AKT/ETS1 signaling in bladder cancer.

Muscle-invasive or metastatic bladder cancer (BCa) is a life-threatening disease for patients, and tumor angiogenesis is believed to play a critical role in the progression of BCa. However, its underlying mechanism of tumor angiogenesis is still poorly understood. In this study, we discovered that RASAL2, a RAS GTPase activating protein, could inhibit BCa angiogenesis based on our shRNA/siRNA knockdown or ectopic cDNA expression experiments. Mechanistically, RASAL2 downregulation could enhance the phosphorylation of AKT and then subsequently upregulate the expression of ETS1 and VEGFA. Furthermore, there was a negative correlation between RASAL2 and VEGFA or CD31 expression in subcutaneous xenograft and human BCa specimens. Taken together, we provide a new insight into the molecular mechanism of BCa progression, in which RASAL2 can be a new therapeutic target.

Evaluation of purinergic mechanism for the treatment of voiding dysfunction: a study in conscious spinal cord-injured rats.

BACKGROUND: To investigate the effect of a selective P2X(3-)P2X(2/3) purinergic receptor antagonist (a-317491) on detrusor hyperreflexia in conscious chronic spinal cord-injured female rats. METHODS: Six chronic spinal cord-transected female Sprague-Dawley rats (290-336 g) were used in this study. Spinal transection at the T8-T9 segmental level was performed using aseptic techniques under halothane anesthesia. Fourteen to 16 weeks after spinal transection, A-317491, a selective P2X(3-)P2X(2/3) purinergic receptor antagonist, was administered intravenously in cystometry studies at increasing doses of 0.03, 0.1, 0.3, 1, 3, 10 and 30 micromol/kg at 40-50 minute intervals. Cystometrograms (CMGs) were performed before and after the administration of each dose of the drug. RESULTS: The continuous filling of CMGs revealed a large number of small-amplitude (> 8 cmH(2)O), non-voiding contractions (NVCs) (average, 9.7 per voiding cycle) preceding voiding contractions (mean amplitude, 31 cmH(2)O; duration, 2.5 minutes), which occurred at an interval of 539 seconds and at a pressure threshold of 5.7 cmH(2)O. When tested in a range of doses (0.03-30 micromol/kg, intravenous), A-317491 in doses between 1 and 30 micromol/kg significantly (p < 0.05) increased the interval between voids by 25%, reduced the number of NVCs by 42-62%, and increased the pressure threshold for voiding by 53-73%, but did not change the amplitude of the duration of the voiding contractions. The effects of the drug were apparent within 10 minutes following administration. CONCLUSION: These results indicate that purinergic mechanisms, presumably involving P2X(3) or P2X(2/3) receptors on bladder C-fiber afferent nerves, play an important role in the detrusor hyperreflexia that occurs after spinal cord injury in rats.