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Updated: Mar 29, 2026

Recording of Inward Rectifying K+ Currents in Freshly Isolated Basilar Artery Smooth Muscle Cells by Patch Clamp Technique
Published on: February 7, 2025
The Effects of Potassium Channels in Human Internal Mammary Artery
Selim Afsar1, Dogus Hemsinli, Sibel Ozyazgan
1Gynecologic Oncology Fellow, Gynecologic Oncology Division, Acx0131;badem University School of Medicine, Istanbul, Turkey.
Background:
Structural and functional changes in potassium channels of vascular smooth muscle cells may contribute to the development of diseases such as hypertension. We aim to investigate the vascular effects of potassium channel openers and blockers in human internal mammary artery (HIMA).
Methods:
Remaining segments of HIMA from 18 consecutive patients undergoing coronary artery bypass surgery were obtained to examine the vascular effects of various potassium channel openers (staurosporine, hydrochlorothiazide and cromakalim) and potassium channel blockers (4-aminopyridin [4-AP], charybdotoxin [CTX] and glibenclamide [GLBC]).
Results:
Noradrenaline (NA)-induced maximal contractions were inhibited by all 3 K+-channel blockers but only fully inhibited by 4-AP (95.6%). Only NA-induced contractions were reversed by CTX. Only K+-induced maximal contractions were significantly inhibited by 4-AP (95.6%, p < 0.05). Only acetylcholine-induced relaxation was fully inhibited by CTX. Only sodium nitroprusside-induced relaxations in potassium chloride-precontracted strips could be reversed by GLBC.
Conclusions:
Drugs affecting potassium channels may be useful in the treatment of hypertension and management of perioperative vasospasm during the coronary artery bypass surgery.
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