The effect of stress on bladder stability

Purpose: This study was designed to examine the effect of stress on the pathophysiology of bladder stability via the Rho-kinase and nitric oxide synthase activity, which are required for muscle contraction and relaxation within the bladder. Materials and Methods: Animal testing was conducted in two separate sessions. In the first experiment, 36 female Sprague-Dawley rats weighing about 230-270g each were employed. 18 rats were placed in the control group and 18 rats were placed in the test group. The second testing was conducted using metabolic cages. Six rats were placed in the control group and six rats were placed in the test group under a stressful environment. Results: The results showed that the frequency of urination was significantly increased with time in the test group (p < 0.05). However, the volume of voided urine decreased, thereby suggesting stress was a cause of overactive bladder. Analysis of bladder tissue for nitric oxide synthase (NOS) and RhoA-binding kinase (ROK α), important components of contraction and relaxation of bladder muscle, revealed that the levels of iNOS and ROK α were significantly increased with continued application of stress. This suggests that stress affects the levels of NOS and ROK α in an overactive bladder to influence contraction and relaxation of the bladder muscle. Conclusions: An increase in the ROKα expression and changes of the NOS expressions in the rats with chronic stress pathophysiologicaly support that stress contributes to the clinical symptoms of overactive bladder.