Characterization of NaV1.6-mediated Na+ currents in smooth muscle cells isolated from mouse vas deferens

Hai Lei Zhu, Atsushi Shibata, Tetsuichiro Inai, Masatoshi Nomura, Yosaburo Shibata, James A. Brock, Noriyoshi Teramoto

Research output: Contribution to journalArticle

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Abstract

Patch-clamp experiments were performed to investigate the behavior of voltage-activated inward currents in vas deferens myocytes from Na V1.6-null mice (NaV1.6-/-) lacking the expression of the Na+ channel gene, Scn8a, and their wild-type littermates (NaV1.6+/+). Immunohistochemistry confirmed expression of NaV1.6 in the muscle of NaV1.6 +/+, but not NaV1.6-/-, vas deferens. PCR analysis revealed that the only β1-subunit gene expressed in NaV1.6+/+ vas deferens was Scn / b. In Na V1.6+/+ myocytes, the threshold for membrane currents evoked by 20 msec voltage ramps (-100mV to 60 mV) was -38.5±4.6mV and this was shifted to a more positive potential (-31.2±4.9 mV) by tetrodotoxin (TTX). In NaV1.6-/- myocytes, the threshold was -30.4±3.4mV and there was no TTX-sensitive current. The Na + current (INa) in NaV1.6+/+ myocytes had a bell-shaped current-voltage relationship that peaked at approximately -10 mV. Increasing the duration of the voltage ramps beyond 20 msec reduced the peak amplitude of INa. INa displayed both fast (τ∼10 msec) and slow (τ∼1 sec) recovery from inactivation, the magnitude of the slow component increasing with the duration of the conditioning pulse (5-40 msec). During repetitive activation (5-40 msec pulses), INa declined at stimulation frequencies > 0.5 Hz and at 10 Hz≤50% of the current remained. These findings indicate that INa is due solely to NaV1.6 in NaV1.6+/+ myocytes. The gating properties of these channels suggest they play a major role in regulating smooth muscle excitability, particularly in response to rapid depolarizing stimuli.

Original languageEnglish
Pages (from-to)234-243
Number of pages10
JournalJournal of cellular physiology
Volume223
Issue number1
DOIs
Publication statusPublished - Apr 1 2010

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Vas Deferens
Muscle Cells
Smooth Muscle Myocytes
Muscle
Cells
Tetrodotoxin
Electric potential
Architectural Accessibility
Genes
Clamping devices
Chemical activation
Smooth Muscle
Membranes
Recovery
Immunohistochemistry
Muscles
Polymerase Chain Reaction
Experiments

All Science Journal Classification (ASJC) codes

  • Physiology
  • Clinical Biochemistry
  • Cell Biology

Cite this

Zhu, H. L., Shibata, A., Inai, T., Nomura, M., Shibata, Y., Brock, J. A., & Teramoto, N. (2010). Characterization of NaV1.6-mediated Na+ currents in smooth muscle cells isolated from mouse vas deferens. Journal of cellular physiology, 223(1), 234-243. https://doi.org/10.1002/jcp.22032

Characterization of NaV1.6-mediated Na+ currents in smooth muscle cells isolated from mouse vas deferens. / Zhu, Hai Lei; Shibata, Atsushi; Inai, Tetsuichiro; Nomura, Masatoshi; Shibata, Yosaburo; Brock, James A.; Teramoto, Noriyoshi.

In: Journal of cellular physiology, Vol. 223, No. 1, 01.04.2010, p. 234-243.

Research output: Contribution to journalArticle

Zhu, HL, Shibata, A, Inai, T, Nomura, M, Shibata, Y, Brock, JA & Teramoto, N 2010, 'Characterization of NaV1.6-mediated Na+ currents in smooth muscle cells isolated from mouse vas deferens', Journal of cellular physiology, vol. 223, no. 1, pp. 234-243. https://doi.org/10.1002/jcp.22032
Zhu, Hai Lei ; Shibata, Atsushi ; Inai, Tetsuichiro ; Nomura, Masatoshi ; Shibata, Yosaburo ; Brock, James A. ; Teramoto, Noriyoshi. / Characterization of NaV1.6-mediated Na+ currents in smooth muscle cells isolated from mouse vas deferens. In: Journal of cellular physiology. 2010 ; Vol. 223, No. 1. pp. 234-243.
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