Efeito da deficiencia do oxido nitrico e da sildenafila na função do trato urinario : estudo experimental em ratos / Effect of nitric oxide deficiency and the action of sildenal in lower urinary tract : an experimental study in rats

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

The lower urinary tract symptoms (LUTS) are associated with a worsening in patients Quality of Life and lead to substantial costs for society. There is a special interest in the development of effective treatment options, with low morbidity, for detrusor overactivity (DO) secondary to benign prostatic obstruction (BPO). Nitric oxide (NO) has been involved as a neurotransmitter in several sites of the nervous system of mammals, including peripheral synapses of the urogenital tract. Sildenafil has been used in the clinical treatment of men with LUTS associated with BPO, with improvement in symptoms. However, this is just one assumption as it has not been proven by experimental studies and the precise role of sildenafil in the treatment of voiding dysfunction associated with BPO is not known. Objective: The aims of this study were evaluate the urodynamic effects of nitric oxide inhibition synthesis by N-nitro-L-arginine methyl ester (L-NAME), as well the action of sildenafil in the lower urinary tract of rats with chronic deficiency of nitric oxide.Materials and Methods: Twenty-seven adult Wistar rats underwent anesthetized cystometrograms: nine controls (Group 1), eight treated with oral L-NAME (60mg/kg/day dissolved in drinking water) for 30 days (Group 2), four treated with sildenafil only (100µg/kg intravenously, IV) (Group 3) and six treated with oral L-NAME for 30 days followed by acute IV sildenafil (100µg/Kg ) (Group 4). Results: The chronic and systemic administration of L-NAME resulted in a significant increase in non voiding contractions (0,98 ±0,75 versus 2,71 ±0,89), volume threshold (1,26 ±0,38 versus 2,8 ±1,64) and frequency of micturition cycles (1,2 ±0,65 versus 1,79 ±0,78), comparing Groups 1 e 2, respectively. The others parameters were not differences. The intravenous administration of sildenafil to Group 3 animals did not significantly alter the frequency (pre-sildenafil 1,23 ±0,37 versus post-sildenafil 1,3 ±0,15) or amplitude of micturition cycles (pre-sildenafil 8,5 ±3,16 versus post-sildenafila 9,0 ±2,99). A significant difference was found between the groups in relation to: void cycles after administration of sildenafil (1,3 ±0,15 versus 0,35 ±0,25). The amplitude before administration was large in Group 4 (8,50 ±3,16 versus 27,0 ±8,73; Groups 3 e 4, respectively), however become similar to that of the Group 3 animals after sildenafil (9,0 ±2,99 versus 7,5 ±6,6; Groups 3 e 4, respectively). Conclusion: The systemic reduction of nitric oxide increase non voiding contractions and frequency of micturition cycles. The administration of sildenafil in animals with chronic deficiency of nitric oxide decreases the number of micturition cycles as well as the contractions amplitude

ASSUNTO(S)

urinary tract trato urinario oxido nitrico rato como animal de laboratorio urodinâmica sildenafil urodynamic rats

ACESSO AO ARTIGO

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