Open Access

Multiple Nav1.5 isoforms are functionally expressed in the brain and present distinct expression patterns compared with cardiac Nav1.5

  • Authors:
    • Jun Wang
    • Shao‑Wu Ou
    • Yun‑Fei Bai
    • Yun‑Jie Wang
    • Zhi‑Qing David Xu
    • Guo‑Ming Luan
  • View Affiliations

  • Published online on: May 30, 2017     https://doi.org/10.3892/mmr.2017.6654
  • Pages: 719-729
  • Copyright: © Wang et al. This is an open access article distributed under the terms of Creative Commons Attribution License.

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Abstract

It has previously been demonstrated that there are various voltage gated sodium channel (Nav) 1.5 splice variants expressed in brain tissue. A total of nine Nav1.5 isoforms have been identified, however, the potential presence of further Nav1.5 variants expressed in brain neurons remains to be elucidated. The present study systematically investigated the expression of various Nav1.5 splice variants and their associated electrophysiological properties in the rat brain tissue, via biochemical analyses and whole‑cell patch clamp recording. The results demonstrated that adult Nav1.5 was expressed in the rat, in addition to the neonatal Nav1.5, Nav1.5a and Nav1.5f isoforms. Further studies indicated that the expression level ratio of neonatal Nav1.5 compared with adult Nav1.5 decreased from 1:1 to 1:3 with age development from postnatal (P) day 0 to 90. This differed from the ratios observed in the developing rat hearts, in which the expression level ratio decreased from 1:4 to 1:19 from P0 to 90. The immunohistochemistry results revealed that Nav1.5 immunoreactivity was predominantly observed in neuronal cell bodies and processes, whereas decreased immunoreactivity was detected in the glial components. Electrophysiological analysis of Nav1.5 in the rat brain slices revealed that an Na current was detected in the presence of 300 nM tetrodotoxin (TTX), however this was inhibited by ~1 µM TTX. The TTX‑resistant Na current was activated at ‑40 mV and reached the maximum amplitude at 0 mV. The results of the present study demonstrated that neonatal and adult Nav1.5 were expressed in the rat brain and electrophysiological analysis further confirmed the functional expression of Nav1.5 in brain neurons.
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July-2017
Volume 16 Issue 1

Print ISSN: 1791-2997
Online ISSN:1791-3004

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Spandidos Publications style
Wang J, Ou SW, Bai YF, Wang YJ, Xu ZQD and Luan GM: Multiple Nav1.5 isoforms are functionally expressed in the brain and present distinct expression patterns compared with cardiac Nav1.5. Mol Med Rep 16: 719-729, 2017
APA
Wang, J., Ou, S., Bai, Y., Wang, Y., Xu, Z.D., & Luan, G. (2017). Multiple Nav1.5 isoforms are functionally expressed in the brain and present distinct expression patterns compared with cardiac Nav1.5. Molecular Medicine Reports, 16, 719-729. https://doi.org/10.3892/mmr.2017.6654
MLA
Wang, J., Ou, S., Bai, Y., Wang, Y., Xu, Z. D., Luan, G."Multiple Nav1.5 isoforms are functionally expressed in the brain and present distinct expression patterns compared with cardiac Nav1.5". Molecular Medicine Reports 16.1 (2017): 719-729.
Chicago
Wang, J., Ou, S., Bai, Y., Wang, Y., Xu, Z. D., Luan, G."Multiple Nav1.5 isoforms are functionally expressed in the brain and present distinct expression patterns compared with cardiac Nav1.5". Molecular Medicine Reports 16, no. 1 (2017): 719-729. https://doi.org/10.3892/mmr.2017.6654