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The role of nitric oxide (NO) in the expression of the human intermediate and small conductance calcium‐activated potassium channels, KCa3.1 and KCa2.3
Author(s) -
Jones Heather Marie,
Hussain Yusaf M
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.955.8
Subject(s) - chemistry , sodium nitroprusside , nitric oxide , calcium activated potassium channel , nitric oxide synthase , potassium channel , calcium , vascular smooth muscle , potassium , sk channel , biophysics , potassium channel blocker , biochemistry , endocrinology , ion channel , biology , receptor , organic chemistry , smooth muscle
Modulation of the calcium‐activate potassium channels that play a role in vascular smooth relaxation may lead to changes in blood pressure by altering vessel tone. Nitric oxide (NO) is an intermediate molecule released from vascular endothelial cells which also will regulate vascular tone. This project hypothesized that exogenous NO will increase expression of calcium‐activated potassium channels to modulate vascular smooth muscle hyperpolarization and relaxation. Additionally, inhibition of endogenous NO will decrease expression of these channels. Total protein expression levels of the intermediate conductance calcium‐activated potassium channel, KCa3.1, and the small conductance calcium‐activated potassium channel, KCa2.3 were examined in this study. Cells endogenously expressing KCa3.1 and KCa2.3 were treated with increasing concentrations (1.0, 2.5 and 10.0 μM) of NO donors and a nitric oxide synthase inhibitor for varying incubation periods (4.0, 8.0 and 12.0 hours). The NO donors used were sodium nitroprusside (SNP) and n‐nitrosoglutathione (GSNO) and the nitric oxide synthase inhibitor used was Nω‐Nitro‐L‐Arginine Methyl Ester Hydrochloride (L‐NAME). Total protein from the treated cells was quantified and equal protein was run on SDS‐PAGE and protein bands were quantified and normalized to b‐actin. Concurrent, non‐treated cells were grown and run as a comparison at each time point. Western blots were scanned and bands intensity used as an indication of expression and quantified using ImageJ. Results showed that SNP significantly increased expression of KCa3.1 at all concentrations of the donor and between the 4 and 8 hour time intervals. The expression of KCa2.3 was also increased in the presence of SNP. Inhibition of KCa3.1 expression by L‐NAME was seen at a concentration of 2.5 μM at 8 hours (p = 0.032) and there was no significant inhibition of the KCa2.3 with L‐NAME. This study demonstrated a potential therapeutic effect that can be obtained in hypertensive patients by applying SNP and GSNO to increase expression of the KCa3.1 and KCa2.3 channels, which will play a role in increased endothelial derived hyperpolarization of vascular smooth muscle.