Document Detail


Endothelial AMP-Activated Protein Kinase Regulates Blood Pressure and Coronary Flow Responses Through Hyperpolarization Mechanism in Mice.
MedLine Citation:
PMID:  24855056     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
OBJECTIVE: Vascular endothelium plays an important role to maintain cardiovascular homeostasis through several mechanisms, including endothelium-dependent hyperpolarization (EDH). We have recently demonstrated that EDH is involved in endothelial metabolic regulation in mice. However, it remains to be examined whether AMP-activated protein kinase (AMPK), an important metabolic regulator, is involved in EDH and if so, whether endothelial AMPK (eAMPK) plays a role for circulatory regulation.
APPROACH AND RESULTS: We examined the role of eAMPK in EDH, using mice with endothelium-specific deficiency of α-catalytic subunit of AMPK, either α1 (eAMPKα1 (-/-)α2 (+/+)) or α2 (eAMPKα1 (+/+)α2 (-/-)) alone or both of them (eAMPKα1 (-/-)α2 (-/-)). We performed telemetry, organ chamber, electrophysiological, and Langendorff experiments to examine blood pressure, vascular responses, hyperpolarization of membrane potential, and coronary flow responses, respectively. Hypertension was noted throughout the day in eAMPKα1 (-/-)α2 (-/-) and eAMPKα1 (-/-)α2 (+/+) but not in eAMPKα1 (+/+)α2 (-/-) mice when compared with respective control. Importantly, endothelium-dependent relaxations, EDH, and coronary flow increase were all significantly reduced in eAMPKα1 (-/-)α2 (-/-) and eAMPKα1 (-/-)α2 (+/+) but not in eAMPKα1 (+/+)α2 (-/-) mice. In contrast, endothelium-independent relaxations to sodium nitroprusside (a NO donor), NS-1619 (a Ca(2+)-activated K(+) channel opener), and exogenous H2O2 were almost comparable among the groups. In eAMPKα1 (-/-)α2 (-/-) mice, antihypertensive treatment with hydralazine or long-term treatment with metformin (a stimulator of AMPK) failed to restore EDH-mediated responses.
CONCLUSIONS: These results provide the first direct evidence that α1 subunit of eAMPK substantially mediates EDH responses of microvessels and regulates blood pressure and coronary flow responses in mice in vivo, demonstrating the novel role of eAMPK in cardiovascular homeostasis.
Authors:
Budbazar Enkhjargal; Shigeo Godo; Ayuko Sawada; Nergui Suvd; Hiroki Saito; Kazuki Noda; Kimio Satoh; Hiroaki Shimokawa
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2014-5-22
Journal Detail:
Title:  Arteriosclerosis, thrombosis, and vascular biology     Volume:  -     ISSN:  1524-4636     ISO Abbreviation:  Arterioscler. Thromb. Vasc. Biol.     Publication Date:  2014 May 
Date Detail:
Created Date:  2014-5-23     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9505803     Medline TA:  Arterioscler Thromb Vasc Biol     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Copyright Information:
© 2014 American Heart Association, Inc.
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