alexa Role of ion channels in acute and chronic responses of the pulmonary vasculature to hypoxia.
Genetics & Molecular Biology

Genetics & Molecular Biology

Human Genetics & Embryology

Author(s): Weir EK, Olschewski A

Abstract Share this page

Abstract Localized alveolar hypoxia causes constriction of the small resistance pulmonary arteries, thus diverting the desaturated, mixed-venous blood to better ventilated areas of the lung. Although modulated by endothelial vasoactive substances, the constrictor response to hypoxia is intrinsic to the smooth muscle cell. Ion channels are important elements in two of the three components of the response. Hypoxia inhibits several potassium channels (voltage-gated and TASK), leading to membrane depolarization and calcium entry through L-type channels. It also causes release of calcium from the sarcoplasmic reticulum, with consequent repletion through store-operated calcium channels. Finally, the effect of the rise in cytosolic calcium is amplified by enhanced calcium sensitivity of the actin/myosin interaction, achieved by the hypoxia-induced increase in Rho-kinase activity. The change in oxygen tension that stimulates these three "executive" components is signaled by a change in the redox status of the smooth muscle cell and probably by downstream changes in G-proteins. Ion channels also play a critical role in the vascular remodeling that results in chronic hypoxic pulmonary hypertension, seen when all the pulmonary vascular bed is hypoxic, at high altitude and in patients with chronic lung diseases. The same inhibition of potassium channels and influx of calcium results in high cytosolic levels of potassium and calcium. These, respectively, lead to inhibition of apoptosis and an increase in cellular proliferation. A better understanding of the pathophysiology of hypoxic pulmonary vasoconstriction and vascular remodeling will enable the design of better treatments for hypoxic and other forms of pulmonary hypertension. This article was published in Cardiovasc Res and referenced in Human Genetics & Embryology

Relevant Expert PPTs

Relevant Speaker PPTs

Recommended Conferences

Relevant Topics

Peer Reviewed Journals
 
Make the best use of Scientific Research and information from our 700 + peer reviewed, Open Access Journals
International Conferences 2017-18
 
Meet Inspiring Speakers and Experts at our 3000+ Global Annual Meetings

Contact Us

 
© 2008-2017 OMICS International - Open Access Publisher. Best viewed in Mozilla Firefox | Google Chrome | Above IE 7.0 version
adwords