2. Second, in OSA and controls alike, regional α-adrenergic block enhances hypoxia-induced vasodilation in the forearm by a similar degree. In fact, after adrenergic blockade, RC vasodilation was more sensitive to hypoxia-induced increases in right ventricular (RV) mechanical function, consistent with an α-adrenergic-mediated constraint of RC hyperemia during hypoxia in the normal, unblocked condition. At end hypoxia after phentolamine, the increase of brachial blood flow above baseline was similar (OSA vs. controls +61 ± 16 vs. +48 ± 6%; P = NS). Vasodilation refers to the widening of the arteries and large blood vessels. To determine whether hypoxia is associated with... Hypoxia-induced vasodilation and effects of regional phentolamine in awake patients with sleep apnea | Journal of Applied Physiology Login to your account Taken together, these findings suggest that during acute hypoxia in awake patients with OSA, neural vasoconstrictor activity is offset by enhanced metabolic vasodilator activation. It is unclear how such a mechanism would cause hypoxia-induced vasodilation because capillaries lack smooth muscle to respond to NO. High Alt Med Biol. The fact that the end-tidal CO 2 was not influenced by hypoxia virtually excludes the distorting influence of changes in P co 2 on hypoxia-induced cerebral vasodilation in the present study . It is a natural process that occurs in response to low oxygen levels or increases in body temperature. Lidocaine impairs vasorelaxation mediated by a K + channel opener, suggesting that this antiarrhythmic drug may inhibit hypoxia-induced vasodilation mediated by K + channels. Animal instrumentation Hypoxia-Induced Vasodilation of Precapillary Arterioles in Vivo Is Attenuated in HO-2–Null Mice and Abolished in CBS-Null Mice. Hypoxic pulmonary vasoconstriction (HPV), also known as the Euler-Liljestrand mechanism, is a physiological phenomenon in which small pulmonary arteries constrict in the presence of alveolar hypoxia (low oxygen levels). Hypoxia-induced vasodilation in the right coronary circulation of conscious dogs: Role of adrenergic activation Srinath Setty , Pu Zong , Wei Sun , Johnathan D. Tune , and H. Fred Downey Proposed mechanisms for hypoxia-induced vasodilation at rest and during exercise. By redirecting blood flow from poorly-ventilated lung regions to well-ventilated lung regions, HPV is thought to be the primary mechanism underlying ventilation/perfusion … Hypoxia induces vasodilation, partly via the activation of K + channels. Materials and methods 2.1. 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