Objective To explore the distribution of interstitial cells of Cajal (ICCs) in normal rat bladder and its effects on detrusor contraction.  Methods Detrusor tissue pieces of  about 3 mm×4 mm were obtained from the dome

triangle

lateral or base of rat bladder. The c-kit positive cells were detected by immunofluorescent staining. Detrusor strips of 2 mm×7 mm were dissected from the same sites respectively for muscle tone determination. The frequency and amplitude of the detrusor strips were compared among different sites of bladder.  Results ICCs did exist in rat bladder

and had different distribution in different sites of bladder. There were more ICCs in the dome and triangle than in the lateral or base of bladder (P0.05)

and there was no difference between the dome and triangle or between the lateral and base. The contraction of strips in different sites varied according to the distribution of ICCs. The amplitude and frequency of strips from the dome and triangle of bladder were significantly higher than those from the lateral and base (P0.05).  The contraction amplitude and frequency of strips were positively correlated with the number of ICCs (P0.05).  Conclusion ICCs is unevenly distributed in rat bladder

and the contraction amplitude and frequency of detrusor strips are correlated with the number of ICCs in different sites of bladder.