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Open Access Highly Accessed Research article

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

Jinxu Liu1, Huiyin Tu1, Dongze Zhang1, Hong Zheng2 and Yu-Long Li12*

Author Affiliations

1 Department of Emergency Medicine, University of Nebraska Medical Center, Omaha, NE, 68198, USA

2 Department of Cellular & Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, 68198, USA

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BMC Neuroscience 2012, 13:129  doi:10.1186/1471-2202-13-129

Published: 25 October 2012

Abstract

Background

The 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.

Results

Whole-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.

Conclusion

Differentiation 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.

Keywords:
Action potential; Na+ channel; NG108-15 cell; Patch clamp; Single-cell real-time PCR; Western blot