<正>Objective: To explore a myogenic basis of the spontaneous contractions on the rat bladder smooth muscle strip in a detrusor instability （DI） model in vitro

and to study a nerve blocker’s cocktail affecting the spontaneous contractions as well as electrical stimulated contractile response. Methods: DI model rats were made by partial bladder outlet obstruction （BOO） and confirmed by the filling cystome-try. Detrusor strip was dissected from fresh bladder

fixed for an isometric tension trial. The contractions were recorded during electrical stimulation or exposure to some agents. Results: The cocktail diminished the nerve-mediated contractile response effectively in DI preparation. DI’s spontaneous contractions remained during the presence of the cocktail with a significant change in its contractile amplitude. Conclusion : With the local nerve-concerned factors abolishment by the cocktail

the DI bladder preparations still have the spontaneous contractions

indicating a myogenic basis from themselves.