[The pathophysiology underlying overactive bladder syndrome possibly due to benign prostatic hyperplasia].

The pathophysiology in the development of overactive bladder syndrome (OAB) possibly due to benign prostatic hyperplasia (BPH) has not fully been understood. The clinical study in male outpatients aged over 50 years with lower urinary tract symptoms showed that the frequency of urgency was significantly associated with aging, bladder outlet obstruction (BOO) and benign prostatic enlargement (BPE). From the results of the experiments we did using rats, the mechanisms underlying the development of OAB were suggested as follows. The functional impairment of acetylcholine neuron in the central nervous system is induced by aging and decreases the bladder capacity. Non-voiding contractions of the bladder may have some bearing on OAB associated with BOO. The C-fiber in the urethra may be involved in the generation of the detrusor overactivity associated with BPE. These results showed that the pathophysiology of OAB related to BPH is quite complex, suggesting that a multidisciplinary approach is necessary for the treatment.