Abstract: AIM: To investigate the dilation effect of isosorbide dinitrate (ISDN) on the rat urine bladder rings.METHODS: The values of the mean contraction tension, maximum amplitude and frequency of rat urine bladder rings were measured. The activity of nitric oxide synthase (NOS) and the content of nitric oxide (NO) were measured in the rat urine bladder tissue pre-incubated with ISDN (10^-4 mol/L) for 1 h.RESULTS: ISDN (10^-5 mol/L, 10^-4 mol/L) could inhibit the mean contractile tension, maximum amplitude and frequency of spontaneous rhythmic contractions of rat urine bladder pre-contracted with ACh (10^-4 mol/L). However, there was no significant change to the rings pre-contracted with KCl (4×10^-4 mol/L). And the activity of NOS and the content of NO were elevated in the rat urine bladder tissue pre-incubated with ISDN.CONCLUSION: ISDN can induce relaxation on rat isolated bladder detrusor muscle rings pre-contracted with ACh, and the mechanism is possibly related to the activation of the nitric oxide synthase and the elevation of NO level.

Key words: Isosorbide dinitrate, Urine bladder detrusor, Dilation, Nitric oxide synthase, Rat