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

• Main Authors: Liu Jinxu, Tu Huiyin, Zhang Dongze, Zheng Hong, Li Yu-Long
• Format: Article
• Language: English
• Published: BMC 2012-10-01
• Series: BMC Neuroscience
• Subjects: Action potential; Na⁺ channel; NG108-15 cell; Patch clamp; Single-cell real-time PCR; Western blot
• Online Access: http://www.biomedcentral.com/1471-2202/13/129

<p>Abstract</p> <p>Background</p> <p>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.</p> <p>Results</p> <p>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.</p> <p>Conclusion</p> <p>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.</p>