Journal article
Sodium leak channel, non-selective contributes to the leak current inhuman myometrial smooth muscle cells from pregnant women
Molecular human reproduction, Vol.21(10), pp.816-824
10/01/2015
DOI: 10.1093/molehr/gav038
PMCID: PMC4586347
PMID: 26134120
Abstract
Uterine contractions are tightly regulated by the electrical activity of myometrial smooth muscle cells (MSMCs). These cells require a depolarizing current to initiate Ca2+ influx and induce contraction. Cationic leak channels, which permit a steady flow of cations into a cell, are known to cause membrane depolarization in many tissue types. Previously, a Gd3+-sensitive, Na+-dependent leak currentwas identified in the rat myometrium, but the presence of such a current in human MSMCs and the specific ion channel conducting this current was unknown. Here, we report the presence of a Na+-dependent leak current in human myometrium and demonstrate that the Na+-leak channel, NALCN, contributes to this current. We performed whole-cell voltage-clamp on fresh and cultured MSMCs from uterine biopsies of term, non-laboring women and isolated the leak currents by using Ca2+ and K+ channel blockers in the bath solution. Ohmic leak currents were identified in freshly isolated and cultured MSMCs with normalized conductances of 14.6 pS/pF and 10.0 pS/pF, respectively. The myometrial leak current was significantly reduced (P < 0.01) by treating cells with 10 mu M Gd3+ or by superfusing the cells with a Na+-free extracellular solution. Reverse transcriptase PCR and immunoblot analysis of uterine biopsies from term, non-laboring women revealed NALCN messenger RNA and protein expression in the myometrium. Notably, similar to 90% knockdown of NALCN protein expression with lentivirus-delivered shRNA reduced the Gd3+-sensitive leak current density by 42% (P < 0.05). Our results reveal that NALCN, in part, generates the leak current in MSMCs and provide the basis for future research assessing NALCN as a potential molecular target for modulating uterine excitability.
Details
- Title: Subtitle
- Sodium leak channel, non-selective contributes to the leak current inhuman myometrial smooth muscle cells from pregnant women
- Creators
- Erin L. Reinl - Washington University in St. LouisRafael Cabeza - University of IowaIsmail A. Gregory - Washington University in St. LouisAlison G. Cahill - Washington University in St. LouisSarah K. England - Washington University in St. Louis
- Resource Type
- Journal article
- Publication Details
- Molecular human reproduction, Vol.21(10), pp.816-824
- Publisher
- Oxford Univ Press
- DOI
- 10.1093/molehr/gav038
- PMID
- 26134120
- PMCID
- PMC4586347
- ISSN
- 1360-9947
- eISSN
- 1460-2407
- Number of pages
- 9
- Grant note
- P30NS057105 / NATIONAL INSTITUTE OF NEUROLOGICAL DISORDERS AND STROKE; United States Department of Health & Human Services; National Institutes of Health (NIH) - USA; NIH National Institute of Neurological Disorders & Stroke (NINDS) 1R21HD076677-01; 1F31HD079148-01 / National Institutes of Health; United States Department of Health & Human Services; National Institutes of Health (NIH) - USA 21-FY15-147 / March of Dimes Hope Center Viral Vectors Core R21HD076677 / EUNICE KENNEDY SHRIVER NATIONAL INSTITUTE OF CHILD HEALTH & HUMAN DEVELOPMENT; United States Department of Health & Human Services; National Institutes of Health (NIH) - USA; NIH Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD) P30 NS057105 / P30 Neuroscience Blueprint Interdisciplinary Center Core award
- Language
- English
- Date published
- 10/01/2015
- Academic Unit
- Molecular Physiology and Biophysics
- Record Identifier
- 9984695837802771
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