Abstract
The present study aimed to evaluate the K+ channels activation in vascular relaxation induced by the nitric oxide (NO) donors ruthenium-derived complex (Terpy) and sodium nitroprusside (SNP), as well as its protein expression, on mesenteric resistance arteries (MRA) isolated from renal hypertensive rats (2K-1C) and sham-operated rats (Sham). The NO donors Terpy and SNP induced relaxation with similar efficacy in isolated MRA from both 2K-1C and Sham rats, although SNP was more potent than Terpy. The maximum relaxation induced by Terpy was decreased when the voltagegated potassium channels were blocked in MRA from Sham, but not in 2K-1C rat arteries. The blockade of ATP-sensitive (KATP), big and small conductance Ca2+-activated (SKCa) or inward rectifier (KIR) potassium channels decreased the maximum relaxation induced by Terpy in MRA from Sham and 2K-1C rats. However, the maximum relaxation induced by SNP was inhibited in Sham but not in 2K-1C rats when the big conductance calcium-activated potassium channel was blocked. However, it remained the same when the other potassium channels were blocked. The protein expression of the SKCa and KATP were not altered in 2K-1C hypertensive rat MRA whereas the expression of KV and BKCa were augmented in MRA from 2K-1C rats. Therefore, the potassium channels play different role on the relaxation induced by SNP and Terpy. The activation of different potassium channels and the protein expression of potassium channels may be differently modulated in arteries from 2K-1C hypertensive rats when compared to normotensive rats.
Highlights
Potassium channels play a central role in the maintenance of the electrical potential across the plasma membrane in smooth muscle cells [1]
The maximum relaxation induced by sodium nitroprusside (SNP) was not altered by the voltagedependent potassium channel blocker, 4-aminopiridine (4-AP), both in sham-operated rats (Sham) (ME: 94.5 ± 2.8%, pD2: 6.40 ± 0.30, n=7, Figure 1A) and 2K-1C rat arteries (ME: 92.3 ± 7.2%, pD2: 7.72 ± 0.51, n=4, Figure 1C)
The maximum relaxation induced by Terpy was decreased by the voltage-dependent potassium channel blocker 4-aminopiridine (4AP), in mesenteric resistance arteries from Sham
Summary
Potassium channels play a central role in the maintenance of the electrical potential across the plasma membrane in smooth muscle cells [1]. The potassium channel activity is linked to contractile tone. The factors that regulate the activity of potassium channels may have major influences on tone and on blood vessel diameter and on vascular resistance, blood flow and blood pressure [1]. Potassium channels from different vascular beds, different blood vessels size (i.e. conduit versus resistance blood vessels) or even different segments of the same artery have different properties [2,3,4,5]. These differences may account for the differences in their responses to physiological, pharmacological, or pathological stimuli [6]. Ion channels in the cells which make up the walls of vessels in the microcirculation display unique function or expression patterns that remain largely unexplored [7]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
