ABSTRACT
Objective: To provide electrophysiological evidence for RIN-14B cells as an useful model of enterochromaffin cells (EC) and to study the role of Nav1. 3 channel in the control of its excitability. Methods: Resting membrane potential was recorded and the effects of TTX and ICA-121431 were examined by current-clamp in cultured RIN-14B cells. The effects of TTX and ICA-121431 on Na+ current of RIN-14B cells were examined by voltage-clamp. Results: RIN-14B cells had a resting potential around -60 mV and fired action potentials when stimulated with depolarizing current pulses. The action potential was completely blocked by TTX and inhibited by ICA-121431 in a dose-dependent manner. TTX blocked activation and inactivation of sodium current. In addition ICA-121431 dose-dependently inhibited activation of Na+ current. Conclusion: The action potential of RIN-14B cells is induced by TTX-sensitive sodium channel and the excitability is controlled by Nav1.3. These results suggest RIN-14B cells are similar to EC and it may be a good model of EC.