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Pharmacological dissection of K v 7.1 channels in systemic and pulmonary arteries
Author(s) -
Chadha Preet S,
Zunke Friederike,
Davis Alison J,
Jepps Thomas A,
Linders Joannes TM,
Schwake Michael,
Towart Rob,
Greenwood Iain A
Publication year - 2012
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.2012.01863.x
Subject(s) - mesenteric arteries , methoxamine , medicine , electrical impedance myography , potassium channel , myocyte , cardiology , circulatory system , anatomy , potassium channel blocker , niflumic acid , vasoconstriction , endocrinology , artery , vasodilation , receptor , agonist
BACKGROUND AND PURPOSE The aim of this study was to characterize the functional impact of KCNQ1‐encoded voltage‐dependent potassium channels (K v 7.1) in the vasculature. EXPERIMENTAL APPROACH Mesenteric arteries, intrapulmonary arteries and thoracic aortae were isolated from adult rats. K v 7.1 channel expression was established by fluorescence immunocytochemistry. Wire myography determined functionality of these channels in response to selective blockers and activators. Xenopus oocytes expressing K v 7.1 channels were used to assess the effectiveness of selective K v 7.1 channel blockers. KEY RESULTS K v 7.1 channels were identified in arterial myocytes by immunocytochemistry. K v 7.1 blockers HMR1556, L‐768,673 (10 µM) and JNJ39490282 (JNJ282; 1 µM) had no contractile effects in arteries, whereas the pan‐K v 7 channel blocker linopirdine (10 µM) evoked robust contractions. Application of two compounds purported to activate K v 7.1 channels, L‐364 373 (R‐L3) and mefenamic acid, relaxed mesenteric arteries preconstricted by methoxamine. These responses were reversed by HMR1556 or L‐768,673 but not JNJ282. Similar effects were observed in the thoracic aorta and intrapulmonary arteries. CONCLUSIONS AND IMPLICATIONS In contrast to previous assumptions, K v 7.1 channels expressed in arterial myocytes are functional ion channels. Although these channels do not appear to contribute to resting vascular tone, K v 7.1 activators were effective vasorelaxants.