Objective    To investigate the role of bladder interstitial cells of Cajal (ICCs) in regulating the excitability of detrusor myocytes.     Methods    1)Ultrastructural connection between ICCs and detrusor myocytes was detected by transmission electron microscope(TEM). 2) Fluorescence redistribution after photobleaching (FRAP) was carried out to detect the intercellular communication between detrusor myocytes and its neighboring ICCs.     Results    1)Gap junction between the 2 kinds of cells was confirmed by TEM. 2)After target detrusor myocyte was photobleached

fluorescence intensity in detrusor myocytes was recovered gradually. In the meantime

fluorescence intensity in the ICCs neighboring to the target detrusor myocyte was decreased. This indicates a signal transmission from the neighboring ICCs to the target detrusor myocyte.     Conclusion    Structural connection is seen between ICCs and detrusor myocytes. Excitability signals might be transferred from ICCs to detrusor myocyte.