Effect of S-methyl-l-thiocitrulline dihydrochloride on rat micturition reflex

ABSTRACT Objective: To evaluate the effect of neuronal nitric oxide synthase on the striated urethral sphincter and the urinary bladder. Materials and Methods: A coaxial catheter was implanted in the proximal urethra and another one in the bladder of female rats, which were anesthetized with subcutaneous injection of urethane. The urethral pressure with saline continuous infusion and bladder isovolumetric pressure were simultaneously recorded. Two groups of rats were formed. In group I, an intrathecal catheter was implanted on the day of the experiment at the L6-S1 level of the spinal cord; in group II, an intracerebroventricular cannula was placed 5-6 days before the experiment. Results: It was verified that the group treated with S-methyl-L-thio-citrulline, via intrathecal pathway, showed complete or partial inhibition of the urethral sphincter relaxation and total inhibition of the micturition reflexes. The urethral sphincter and the detrusor functions were recovered after L-Arginine administration. When S-methyl-L-thio-citrulline was administered via intracerebroventricular injection, there was a significant increase of urethral sphincter tonus while preserving the sphincter relaxation and the detrusor contractions, at similar levels as before the use of the drugs. Nevertheless there was normalization of the urethral tonus when L-Arginine was applied. Conclusions: The results indicate that, in female rats anaesthetized with urethane, the nNOS inhibitor administrated through the intrathecal route inhibits urethral sphincter relaxation, while intracerebroventricular injection increases the sphincter tonus, without changing bladder function. These changes were reverted by L-Arginine administration. These findings suggest that the urethral sphincter and detrusor muscle function is modulated by nitric oxide

Cystometric analysis of the transplanted bladder

ABSTRACT Objective Cystometric evaluation of the bladder after autotransplant and isogeneic transplant in female rats. Material and Methods Two groups were constituted: (A) bladder autotransplant with two subgroups: R1 – (control) and R2 – (bladder transplant); (B) isogeneic bladder transplant with three subgroups; T1 – (control); T2–T3, two subgroups observed for 30 and 60 days after transplant, respectively. All animals underwent cystometric evaluation. Afterwards, the bladders were removed for histological study. Results The transplanted bladders did not show significant changes in filling/storage and emptying/micturition functions after 30 and 60 days of evolution. Upon macroscopical evaluation, there was good revascularization and the tissue was well preserved. Cystometry results: Did not show significant differences in the micturition pressure in subgroups T2-T3, but did between subgroups R1−R2, T1−T2, and T1−T3. Significant differences were verified in the micturition interval between T1−T3, T2−T3, but not between R1−R2, T1−T2. There was significant difference in the micturition duration between T1−T3 but not between R1−R2, T1−T2 and T2−T3. No fistula was noted on the suture site nor leakage of urine in the abdominal cavity or signs of necrosis or retraction were observed. Conclusions Transplant of the bladder was shown to be a viable procedure. The results indicate that there was structural and functional regeneration of transplanted bladders, and these results indicate that it is possible that vascular endothelium growth and neurogenesis factors are involved and activated in the process of the preservation or survival of the transplanted organ