Intermittent hypoxia in rats increases myogenic tone through loss of hydrogen sulfide activation of large-conductance Ca(2+)-activated potassium channels.

ABSTRACT:

Rationale

Myogenic tone, an important regulator of vascular resistance, is dependent on vascular smooth muscle (VSM) depolarization, can be modulated by endothelial factors, and is increased in several models of hypertension. Intermittent hypoxia (IH) elevates blood pressure and causes endothelial dysfunction. Hydrogen sulfide (H(2)S), a recently described endothelium-derived vasodilator, is produced by the enzyme cystathionine γ-lyase (CSE) and acts by hyperpolarizing VSM.

Objective

Determine whether IH decreases endothelial H(2)S production to increase myogenic tone in small mesenteric arteries.

Methods and results

Myogenic tone was greater in mesenteric arteries from IH than sham control rat arteries, and VSM membrane potential was depolarized in IH in comparison w

SUBMITTER: Jackson-Weaver O 

PROVIDER: S-EPMC3234884 | biostudies-literature | 2011 Jun

REPOSITORIES: biostudies-literature