Response of isolated human neurogenic detrusor smooth muscle to intramural nerve stimulation

The effect of intramural nerve stimulation of isolated strips of human detrusor was investigated and compared with the response of isolated detrusor strips of control bladders. All patients with neurogenic bladder underwent ileocystoplasty in order to resolve intractable incontinence and/or vesicoureteric reflux due to low compliance or severe detrusor uninhibited contractions. The response of isolated strips of neurogenic bladder to field stimulation was significantly greater than the response of isolated strips of control bladders. Tetrodotoxin virtually eliminated the response to field stimulation for both groups. Atropine (10(-6)M) almost completely inhibited the response of control bladder strips to field stimulation (4% of the response remaining), whereas the responses of the strips from neurogenic bladders were inhibited by approximately 70%. Low dose KCl (5 and 10 mM) significantly enhanced the detrusor contractility of control bladders, whereas the response of neurogenic bladders was unchanged. The responses of both groups were significantly inhibited in the presence of 20 mM KCl. The dose response curves and the ED50 values for KCl were similar for both neurogenic and control bladders. The rate of reduction of the response to field stimulation in the presence of zero calcium medium was significantly smaller for the isolated strips of neurogenic bladders than for the control bladders.