The detrusor contraction induced by intramural nerve stimulation in human neurogenic bladders was investigated in comparison with control bladders. All the cases with the neurogenic bladder underwent ileocystoplasty in order to resolve intractable incontinence and/or vesicoureteral ref lux due to low bladder compliance or severe detrusor uninhibited contraction. 1. The dose-response curve and ED50 value for KC1 were not different between neurogenic and control bladders. 2. The response of

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... enic bladders induced by intramural stimulation was significantly stronger than that of control bladders. 3. After application of 10-6 M atropine remaining contraction of neurogenic bladders was significantly greater than that of control bladders, i. e. 28. 4% and 3. 7% respectively. However, 10-6 M tetrodotoxin almost completely inhibited the detrusor contraction in both groups. 4. The subthreshold KC1(5 mM or 10 mM) enhanced the detrusor contractility significantly in control bladders compared to neurogenic bladders. 5. After bathing medium was replaced into Ca-free Krebs' solution, the contractile response was decreased. The contraction of neurogenic bladders in Ca-free solution persisted longer than that of controls. In conclusion, though there was no intrinsic difference in detrusor contractility, contractile response to electrical field stimulation, atropine resistance, enhancement of response by potassium, and contractility in Ca-free solution were significantly different between neurogenic and control bladders.