[Characteristic of age-dependent changes in pial arterial vessels endothelium-dependent hyperpolarization in normotensive and spontaneously hypertensive rats.].

A comparative study of changes in the contribution of endothelium-dependent hyperpolarization (EDH) induced by activation of the intermediate-conductance calcium-activated potassium channels (IKса) channels and the contribution of NO in pial arterial vessels dilation to acetylcholine (ACh) in normotensive (WKY) and spontaneously hypertensive (SHR) rats at the age of 4 and 18 months was conducted. It was found that in WKY, the EDH is mainly expressed in the group of small pial arterial vessels. During aging, the contribution of EDH to the dilatation of small (diameter less than 20 microns) and medium (20-40 microns) vessels decreases, while it increases in arteries with a diameter of more than 40 microns. Hypertension (HT) leads to an increase in the contribution of EDH processes to dilation of vessels of small and medium diameters. Aging, accompanied by long-term HT, reduces the contribution of EDH to dilation. In 18-month-old SHR, this mechanism is expressed only in a group of small vessels. Age-dependent changes in the EDH contribution in pial arterial vessels dilation in WKY and SHR rats are based on the NO synthesis system damage and a change in the NO-mediated contribution in endothelium-dependent vasodilation.