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Large Conductance Ca2+-Activated K+ Channels Contribute to Vascular Function in Nonpregnant Human Uterine Arteries

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Abstract

Large conductance K+ channels (BKCa) are expressed in uterine artery (UA) smooth muscle from nonpregnant and pregnant sheep and contribute to the regulation of basal vascular tone and responses to estrogen and vasoconstrictors. To determine if BKCa are expressed in women and contribute to UA function, we collected UA from nonpregnant women (n = 31) at elective hysterectomy and analyzed for subunit protein, localization with immunohistochemistry, and function using endothelium-denuded rings. UA expresses BKCa α -, β1- and β2-subunit protein. KCl and phenylephrine (PE, an α1-agonist) caused dose-dependent vasoconstriction (P < .001), and UA precontracted with PE dose-dependently relaxed with sodium nitroprusside (SNP;P < .001). Tetraethylammonium chloride (TEA, 0.2–1.0 mM), a BKCainhibitor, dose-dependently increased resting tone (P = .004; 28% ± 5.3% with 1.0 mM), enhanced PE-induced (10−6 M) vasoconstriction (P < .04), and attenuated SNP-induced relaxation at 1.0 mM (P = .02). BKCa are expressed in human UA and modulate vascular function by attenuating vasoconstrictor responses and contributing to nitric oxide-induced vasorelaxation.

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Authors and Affiliations

  1. Division of Neonatal-Perinatal Medicine, Department of Pediatrics, University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Boulevard, Dallas, Texas, 75390, USA

    Charles R. Rosenfeld MD, Kevin DeSpain BS & Xiao-tie Liu MS, MD

  2. Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, USA

    Charles R. Rosenfeld MD & R. Ann Word MD

Authors
  1. Charles R. Rosenfeld MD
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  2. R. Ann Word MD
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  3. Kevin DeSpain BS
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  4. Xiao-tie Liu MS, MD
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Corresponding author

Correspondence to Charles R. Rosenfeld MD.

Additional information

This study was supported by NIH grants HD-08783 (CRR) and HD11149 (RAW).

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Rosenfeld, C.R., Word, R.A., DeSpain, K. et al. Large Conductance Ca2+-Activated K+ Channels Contribute to Vascular Function in Nonpregnant Human Uterine Arteries. Reprod. Sci. 15, 651–660 (2008). https://doi.org/10.1177/1933719108319160

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  • DOI: https://doi.org/10.1177/1933719108319160

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