Key result
Aging accompanied by long-term arterial hypertension reduced the contribution of endothelium-dependent hyperpolarization to pial arterial dilation, limiting it to small vessels <20 μm in 18-month-old SHRs.
Why the study?
The study aimed to examine age-related changes in the contribution of endothelium-dependent hyperpolarization to vascular tone control of cerebral vessels, with and without concomitant long-lasting arterial hypertension.
Aging and long-term arterial hypertension alter the mechanisms of endothelium-dependent hyperpolarization in pial arteries, driven by damage to the NO synthesis system.
The changes that occurred with aging in the contribution of endothelium-dependent hyperpolarization (EDH) to endothelial control over the vascular tone of cerebral vessels were studied with and without concomitant long-lasting arterial hypertension (AH). The study focused on the role of EDH induced by the activation of intermediate-conductance, calcium-activated potassium channels (IKCa) and the impact of NO on the vasodilation of pial arteries to acetylcholine in normotensive (WKY) rats and spontaneously hypertensive rats (SHRs) at the age of 4 and 18 months. It was found that the mechanism of EDH was mainly expressed in a group of small pial arteries in WKY rats. The influence of EDH on the dilatation of small and medium vessels decreased with aging; it increased in the arteries with a diameter of over 40 μm. The contribution of EDH processes to the dilation of small and medium vessels increased with AH. Aging accompanied by long-term AH reduced the contribution of EDH to dilation. In 18-month-old SHRs, this mechanism was expressed only in a group of small vessels with a diameter of less than 20 μm. Age-related changes in the mechanisms of EDH effects on pial arterial dilation in WKY rats and SHRs were based on the damage to the NO synthesis system and the altered role of NO-mediated mechanisms in endothelium-dependent vasodilatation.
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О. П. Горшкова (2021) studied Arterial hypertension and aging. Aging and arterial hypertension vs. Young and normotensive rats was evaluated on Contribution of endothelium-dependent hyperpolarization (EDH) to endothelial control over the vascular tone of cerebral vessels. Aging accompanied by long-term arterial hypertension reduced the contribution of endothelium-dependent hyperpolarization to pial arterial dilation, limiting it to small vessels <20 μm in 18-month-old SHRs.
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