Voltage-gated sodium channel expression and action potential generation in differentiated NG108-15 cells

Jinxu Liu,Hong Zheng,Yu-Long Li,Huiyin Tu,Dongze Zhang

doi:10.1186/1471-2202-13-129

Abstract

BackgroundThe generation of action potential is required for stimulus-evoked neurotransmitter release in most neurons. Although various voltage-gated ion channels are involved in action potential production, the initiation of the action potential is mainly mediated by voltage-gated Na+ channels. In the present study, differentiation-induced changes of mRNA and protein expression of Na+ channels, Na+ currents, and cell membrane excitability were investigated in NG108-15 cells.ResultsWhole-cell patch-clamp results showed that differentiation (9 days) didn’t change cell membrane excitability, compared to undifferentiated state. But differentiation (21 days) induced the action potential generation in 45.5% of NG108-15 cells (25/55 cells). In 9-day-differentiated cells, Na+ currents were mildly increased, which was also found in 21-day differentiated cells without action potential. In 21-day differentiated cells with action potential, Na+ currents were significantly enhanced. Western blot data showed that the expression of Na+ channels was increased with differentiated-time dependent manner. Single-cell real-time PCR data demonstrated that the expression of Na+ channel mRNA was increased by 21 days of differentiation in NG108-15 cells. More importantly, the mRNA level of Na+ channels in cells with action potential was higher than that in cells without action potential.ConclusionDifferentiation induces expression of voltage-gated Na+ channels and action potential generation in NG108-15 cells. A high level of the Na+ channel density is required for differentiation-triggered action potential generation.

Highlights

The generation of action potential is required for stimulus-evoked neurotransmitter release in most neurons
Action potential production is required for neuronal excitation and stimulus-evoked neurotransmitter release, which are involved in neuron-to-neuron communication [13,14]
In order to clarify the relationship between action potential generation and sodium channel density, in this study, we investigated the time-course for differentiation-induced changes of membrane excitability and Na+ channels in NG108-15 cells

Summary

Introduction

The generation of action potential is required for stimulus-evoked neurotransmitter release in most neurons. Exploring cell molecular and electrophysiological properties such as expression and current of ion channels, and action potentials is very important for understanding the physiological and pathophysiological functions of the excitable cells including neurons, muscle cells, and endocrine cells. NG108-15 cell line is a hybrid cell line formed by the fusion of mouse N18TG2 neuroblastoma cells and rat C6BU-1 glioma cells [1] After differentiation, this cell line presents neurite extension, forms synapses, and develops the ultimate neural property of acetylcholine release and specific activities of choline acetyltransferase and acetylcholinesterase [2,3,4]. Action potential production is required for neuronal excitation and stimulus-evoked neurotransmitter release, which are involved in neuron-to-neuron communication [13,14].

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Discussion

Conclusion