Functional expression of NaV1.7 channels in freshly dispersed mouse bronchial smooth muscle cells

Ruth M. Matthews, Eamonn Bradley, Caoimhin S. Griffin, Xin Rui Lim, Nicolas D. Mullins, Mark A. Hollywood, Fionnuala T. Lundy, Lorcan P. McGarvey, Gerard P. Sergeant, Keith D. Thornbury

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)
11 Downloads (Pure)

Abstract

Isolated smooth muscle cells (SMCs) from mouse bronchus were studied using the whole cell patch-clamp technique at ∼21°C. Stepping from -100 mV to -20 mV evoked inward currents of mean amplitude -275 pA. These inactivated (tau = 1.1 ms) and were abolished when external Na+ was substituted with N-Methyl-d-glucamine. In current-voltage protocols, current peaked at -10 mV and reversed between +20 and +30 mV. The V1/2s of activation and inactivation were -25 and -86 mV, respectively. The current was highly sensitive to tetrodotoxin (IC50 = 1.5 nM) and the NaV1.7 subtype-selective blocker, PF-05089771 (IC50 = 8.6 nM), consistent with NaV1.7 as the underlying pore-forming α subunit. Two NaV1.7-selective antibodies caused membrane-delineated staining of isolated SMC, as did a nonselective pan-NaV antibody. RT-PCR, performed on groups of ∼15 isolated SMCs, revealed transcripts for NaV1.7 in 7/8 samples. Veratridine (30 µM), a nonselective NaV channel activator, reduced peak current evoked by depolarization but induced a sustained current of 40 pA. Both effects were reversed by tetrodotoxin (100 nM). In tension experiments, veratridine (10 µM) induced contractions that were entirely blocked by atropine (1 µM). However, in the presence of atropine, veratridine was able to modulate the pattern of activity induced by a combination of U-46619 (a thromboxane A2 mimetic) and PGE2 (prostaglandin E2), by eliminating bursts in favor of sustained phasic contractions. These effects were readily reversed to control-like activity by tetrodotoxin (100 nM). In conclusion, mouse bronchial SMCs functionally express NaV1.7 channels that are capable of modulating contractile activity, at least under experimental conditions.

Original languageEnglish
Pages (from-to)C749-C762
JournalAmerican journal of physiology. Cell physiology
Volume323
Issue number3
Early online date25 Jul 2022
DOIs
Publication statusPublished - 01 Sept 2022
Externally publishedYes

Keywords

  • airway
  • NaV1.7
  • smooth muscle

ASJC Scopus subject areas

  • Physiology
  • Cell Biology

Fingerprint

Dive into the research topics of 'Functional expression of NaV1.7 channels in freshly dispersed mouse bronchial smooth muscle cells'. Together they form a unique fingerprint.

Cite this