Hiroki Horita

Effect of the nitric oxide level in the medial preoptic area on male copulatory behavior in rats

We investigated the influence of the extracellular nitric oxide (NO) level on male copulatory behavior. We confirmed the changes of nitrite (NO2-) and nitrate (NO3-) in the medial preoptic area (MPOA) by administration of the NO precursor L-arginine (L-Arg, 10 mM) or the NO synthase inhibitor NG-monomethyl-L-arginine (L-NMMA, 10 mM) via a dialysis probe. NO2- and NO3- were measured simultaneously by an in vivo microdialysis method coupled with the Griess reaction. L-Arg induced significant elevations of extracellular NO2- and NO3-. L-NMMA significantly reduced NO2- and NO3- levels. We observed male copulatory behavior during infusion of L-Arg or L-NMMA. The mount rate of male rats significantly increased during infusion of L-Arg in the MPOA. Administration of L-NMMA reduced the mount rate. These findings suggested that the elevation of extracellular NO in the MPOA facilitates male copulatory behavior of rats, whereas the decrease of NO reduces their copulatory behavior.We investigated the influence of the extracellular nitric oxide (NO) level on male copulatory behavior. We confirmed the changes of nitrite ([Formula: see text]) and nitrate ([Formula: see text]) in the medial preoptic area (MPOA) by administration of the NO precursorl-arginine (l-Arg, 10 mM) or the NO synthase inhibitor N G-monomethyl-l-arginine (l-NMMA, 10 mM) via a dialysis probe. [Formula: see text] and[Formula: see text] were measured simultaneously by an in vivo microdialysis method coupled with the Griess reaction.l-Arg induced significant elevations of extracellular [Formula: see text]and [Formula: see text].l-NMMA significantly reduced[Formula: see text] and[Formula: see text] levels. We observed male copulatory behavior during infusion ofl-Arg orl-NMMA. The mount rate of male rats significantly increased during infusion ofl-Arg in the MPOA. Administration of l-NMMA reduced the mount rate. These findings suggested that the elevation of extracellular NO in the MPOA facilitates male copulatory behavior of rats, whereas the decrease of NO reduces their copulatory behavior.

Dopamine release in the medial preoptic area during male copulatory behavior in rats

In vivo microdialysis was employed to measure the extracellular concentrations of dopamine (DA) in the medial preoptic area (MPOA) of rats during male sexual activity to look for a correlation with sexual activity. During copulation, the concentration of DA in the MPOA was significantly increased. A significant difference was detected in changes of DA between copulators and non-copulators. These findings were consistent with the assertion that DA neuron activity in the MPOA facilities male copulatory behavior.

RESTORATION OF SEXUAL BEHAVIOR AND DOPAMINERGIC NEUROTRANSMISSION BY LONG TERM EXOGENOUS TESTOSTERONE REPLACEMENT IN AGED MALE RATS

PURPOSE We investigated the effects of long-term testosterone replacement on copulatory behavior and dopaminergic neurotransmission in the medial preoptic area of aged male rats. MATERIALS AND METHODS The rats were divided into 3 groups depending on testosterone replacement. Those in the long-term replacement group were castrated at the age of 12 months and received testosterone replacement thereafter for 12 months. In the short-term replacement group, rats were castrated at the age of 22 months and high or low dose testosterone replacement was done for 2 months. The control group consisted of aged rats 24 months old and young rats 12 weeks old, neither of which had been castrated or received testosterone replacement. We observed sexual behavior in rats of these groups. After a behavioral test, we measured the tissue concentration of dopamine in the MPOA and the change rate of the extracellular dopamine level induced by infusion of N-methyl-D-aspartic acid (NMDA) in the MPOA and compared the long-term replacement and no-replacement groups. RESULTS The rats in the long-term replacement group showed a mount rate at the same level as that of young rats at 6 weeks after starting replacement and it was maintained to 24 months of age. Their mount rate was significantly higher than that of the rats with the short-term replacement. A significantly higher change rate of dopamine release was recognized in the long-term group; however, no significant difference in the concentration of dopamine was recognized between aged rats with long-term replacement and those without replacement. CONCLUSIONS Aged rats (24 months old) with long-term testosterone replacement maintained almost the same level of mount behavior as young rats (12 weeks old). The results imply that long-term testosterone replacement may favorably alter the decline in the process of sexual activity with aging. The restoration by testosterone replacement of dopaminergic activity in the MPOA may be involved in the maintenance of sexual function in aged rats.

Recovery of sexual function after nerve‐sparing radical prostatectomy or cystectomy

Background: The recovery of sexual function (erectile function and frequency of sexual intercourse) over time after nerve‐sparing radical prostatectomy or cystoprostatectomy was evaluated.

The correlation between penile tumescence measured by the erectometer and penile rigidity by the RigiScan

The goal of this study was to evaluate the correlation between increments of penile tumescence and penile rigidity measured by the erectometer and the RigiScan, respectively.

α1-blocker tamsulosin as initial treatment for patients with benign prostatic hyperplasia: 5-year outcome analysis of a prospective multicenter study.

To comprehensively analyze the 5‐year outcomes of tamsulosin treatment for patients with benign prostatic hyperplasia.

The Add-On Effect of Solifenacin for Patients with Remaining Overactive Bladder after Treatment with Tamsulosin for Lower Urinary Tract Symptoms Suggestive of Benign Prostatic Obstruction

Objectives. To investigate the add-on effect of solifenacin for Japanese men with remaining overactive bladder (OAB) symptoms after tamsulosin monotherapy for lower urinary tract symptoms (LUTS) suggestive of benign prostatic obstruction (BPO) in real-life clinical practice. Methods. Patients aged ≥ 50 having remaining OAB symptoms (≥ 3 of OAB symptom score (OABSS) with ≥2 of urgency score) after at least 4 weeks treatment by 0.2 mg of tamsulosin for BPO/LUTS received 2.5 or 5.0 mg of solifenacin for 12 weeks. The International Prostate Symptom Score (IPSS), QOL index and OABSS, maximum flow rate (Qmax) and postvoid residual urine volume (PVR) were determined. Results. A total of 48 patients (mean age 72.5 years) completed the study. There were significant improvement in IPSS (15.1 to 11.2) and QOL index (4.2 to 3.0) by add-on of solifenacin. Although the IPSS storage symptom score was significantly improved, there were no changes observed in the IPSS voiding symptom score. The OABSS showed significant improvement (8.0 to 4.8). No changes were observed in Qmax and PVR. Conclusions. Under the supervision of an experienced urologist, the additional administration of solifenacin to patients with BPO/LUTS treated with tamsulosin, is effective in controlling remaining OAB symptoms.

Extraperitoneal bladder rupture secondary to rectal impalement

Impalement injury to both the urinary bladder and the rectum is a rare occurrence. A 45‐year‐old man was referred to our hospital because he had been stabbed through the internal femoral skin by a steel bar. Retrograde cystography and computed tomography failed to demonstrate bladder rupture. We carried out cystoscopy (CS) because of the existence of gross hematuria and found a penetrating wound in the posterior wall. Colon fiberscopy revealed two wounds in the rectum, one of which communicated with the bladder. A diagnostic laparoscopy revealed no associated injuries in the peritoneal cavity. Vesicorectal injury was diagnosed and treatment included transanal closure of fistulas and indwelling ureteral and urethral catheters. Postoperative CS revealed complete closure of the injury.

Gatifloxacin treatment for chronic prostatitis: a prospective multicenter clinical trial

Antimicrobial treatment is usually used for chronic prostatitis. However, the efficacy of such treatment has not been fully evaluated. We conducted a study to evaluate the efficacy of gatifloxacin for patients with chronic prostatitis using the Japanese version of the National Institutes of Health Chronic Prostatitis Symptom Index (JPN-NIH CPSI). The study included 46 patients for final analysis. Patients who were younger than 65 years of age were treated with 200 mg gatifloxacin twice daily, and those who were 65 years and older were treated with 100 mg gatifloxacin twice daily, for 4–8 weeks. The study consisted of 10 patients in category II, 13 in category IIIA, 11 in category IIIB, and 12 who were unclassified. The gatifloxacin treatment resulted in significant reductions in the scores on the JPN-NIH CPSI. Of the total number of patients, 58.1% and 27.9% were 25% and 50% responders, respectively, 4 weeks after treatment, and these figures improved to 66.7% and 33.3%, respectively, 8 weeks after treatment. No significant difference was found in the changes in symptom scores between Category II and Category IIIA/IIIB groups. In conclusion, gatifloxacin treatment improved the symptoms in patients with chronic bacterial and nonbacterial prostatitis. This study is the first in this country to evaluate the efficacy of antimicrobial treatment for chronic prostatitis by using the NIH CPSI.

Palonosetron with aprepitant plus dexamethasone to prevent chemotherapy-induced nausea and vomiting during gemcitabine/cisplatin in urothelial cancer patients

To evaluate the appearance of chemotherapy‐induced nausea and vomiting, and to compare the antiemetic efficacy of the triple combination of palonosetron, aprepitant and dexamethasone with that of our old regimen using first‐generation 5‐hydroxytryptamine 3‐receptor antagonists and dexamethasone during gemcitabine and cisplatin chemotherapy in patients with advanced urothelial cancer.