Objective To ascertain the presence of pacemaker-like current in interstitial cells of Cajal (ICCs) in the bladder of adult guinea pigs. Methods Primarily cultured bladder ICC of adult guinea pigs were harvested by collagenase digestion. Hyperrepolarization-activated inward current (Ih) and pacemaker specific current were recorded using whole-cell patch clamp technique. Results There was significant difference in resting membrane potential and membrane capacitance between ICCs and detrusor myocytes. Ih was confirmed in the ICCs

but not in the detrusor myocytes. Conclusion We have confirmed the existence of the specific pacemaker current in the ICCs in the bladder of adult guinea pigs

implying that ICCs might play an important role as pacemaker in the bladder.