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Reduced activity of SKC a and Na-K ATPase underlies the accelerated impairment of EDH-type relaxations in mesenteric arteries of aging spontaneously hypertensive rats.

Kong BW, Man RY, Gao Y, Vanhoutte PM, Leung SW - Pharmacol Res Perspect (2015)

Bottom Line: EDH-type relaxation in SHR was smaller than that in WKY arteries, and further reduction occurred with aging.Pharmacological experiments suggested a reduced involvement of SKC a and Na-K ATPase and activation of adenosine monophosphate-activated protein kinase and silent information regulator T1 (sirtuin-1; SIRT1) in mesenteric arteries of 12-week-old SHR.These pharmacological findings suggest that in superior mesenteric arteries of the rat, the reduction in EDH-type relaxation occurs with aging and that such a reduction is exacerbated in hypertension.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong Hong Kong SAR, China.

ABSTRACT
Aging is accompanied by endothelial dysfunction due to reduced bioavailability of nitric oxide (NO) and/or reduced endothelium-dependent hyperpolarizations (EDH). This study examines the hypothesis that hypertension aggravates the impairment of EDH-type relaxation due to aging. EDH-type relaxations were studied in superior mesenteric arteries isolated from Wistar Kyoto (WKY) and spontaneously hypertensive (SHR) rats of 12, 36, 60, and 72 weeks of age. EDH-type relaxations in WKY were reduced with aging, and this was associated with an impairment of the function of small-conductance calcium-activated potassium channels (SKC a) and sodium-potassium ATPase (Na-K ATPase). EDH-type relaxation in SHR was smaller than that in WKY arteries, and further reduction occurred with aging. Pharmacological experiments suggested a reduced involvement of SKC a and Na-K ATPase and activation of adenosine monophosphate-activated protein kinase and silent information regulator T1 (sirtuin-1; SIRT1) in mesenteric arteries of 12-week-old SHR. These pharmacological findings suggest that in superior mesenteric arteries of the rat, the reduction in EDH-type relaxation occurs with aging and that such a reduction is exacerbated in hypertension. The latter exacerbation appears to involve proteins associated with the process of cellular senescence and is related to impaired function of SKC a and Na-K ATPase, a phenomenon that is also observed in mesenteric arteries of older normotensive rats.

No MeSH data available.


Related in: MedlinePlus

The mechanism underlying the impairment of endothelium-dependent hyperpolarization (EDH)-type relaxations in aging or hypertensive rats. Aging or hypertension causes the dysfunction of small-conductance calcium-activated potassium chanels (SKCa) and sodium-potassium ATPase (Na-K ATPase), thus impairing EDH-mediated responses. In young hypertensive animals, the impairment is compensated by the facilitation of the activity of intermediate-conductance calcium-activated potassium chanels (IKCa), and the activation of adenosine monophosphate-activated protein kinase (AMPK) and silent information regulator T1 (sirtuin-1; SIRT1).
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fig08: The mechanism underlying the impairment of endothelium-dependent hyperpolarization (EDH)-type relaxations in aging or hypertensive rats. Aging or hypertension causes the dysfunction of small-conductance calcium-activated potassium chanels (SKCa) and sodium-potassium ATPase (Na-K ATPase), thus impairing EDH-mediated responses. In young hypertensive animals, the impairment is compensated by the facilitation of the activity of intermediate-conductance calcium-activated potassium chanels (IKCa), and the activation of adenosine monophosphate-activated protein kinase (AMPK) and silent information regulator T1 (sirtuin-1; SIRT1).

Mentions: In conclusion, the present data suggest that EDH-type response in the rat mesenteric artery undergoes an age-dependent impairment, which is also observed in hypertensive rats but is exacerbated when aging is associated with hypertension. The impairment due to aging or hypertension can be attributed to reduced involvement of SKCa (Fig.8), suggesting that high arterial blood pressure may cause similar damage to endothelial function as aging. The remaining EDH-type relaxation in young hypertensive animal appears to depend on the activation of SIRT1 and AMPK, which may serve to combat the impairment of endothelium-dependent relaxation in hypertension.


Reduced activity of SKC a and Na-K ATPase underlies the accelerated impairment of EDH-type relaxations in mesenteric arteries of aging spontaneously hypertensive rats.

Kong BW, Man RY, Gao Y, Vanhoutte PM, Leung SW - Pharmacol Res Perspect (2015)

The mechanism underlying the impairment of endothelium-dependent hyperpolarization (EDH)-type relaxations in aging or hypertensive rats. Aging or hypertension causes the dysfunction of small-conductance calcium-activated potassium chanels (SKCa) and sodium-potassium ATPase (Na-K ATPase), thus impairing EDH-mediated responses. In young hypertensive animals, the impairment is compensated by the facilitation of the activity of intermediate-conductance calcium-activated potassium chanels (IKCa), and the activation of adenosine monophosphate-activated protein kinase (AMPK) and silent information regulator T1 (sirtuin-1; SIRT1).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4492766&req=5

fig08: The mechanism underlying the impairment of endothelium-dependent hyperpolarization (EDH)-type relaxations in aging or hypertensive rats. Aging or hypertension causes the dysfunction of small-conductance calcium-activated potassium chanels (SKCa) and sodium-potassium ATPase (Na-K ATPase), thus impairing EDH-mediated responses. In young hypertensive animals, the impairment is compensated by the facilitation of the activity of intermediate-conductance calcium-activated potassium chanels (IKCa), and the activation of adenosine monophosphate-activated protein kinase (AMPK) and silent information regulator T1 (sirtuin-1; SIRT1).
Mentions: In conclusion, the present data suggest that EDH-type response in the rat mesenteric artery undergoes an age-dependent impairment, which is also observed in hypertensive rats but is exacerbated when aging is associated with hypertension. The impairment due to aging or hypertension can be attributed to reduced involvement of SKCa (Fig.8), suggesting that high arterial blood pressure may cause similar damage to endothelial function as aging. The remaining EDH-type relaxation in young hypertensive animal appears to depend on the activation of SIRT1 and AMPK, which may serve to combat the impairment of endothelium-dependent relaxation in hypertension.

Bottom Line: EDH-type relaxation in SHR was smaller than that in WKY arteries, and further reduction occurred with aging.Pharmacological experiments suggested a reduced involvement of SKC a and Na-K ATPase and activation of adenosine monophosphate-activated protein kinase and silent information regulator T1 (sirtuin-1; SIRT1) in mesenteric arteries of 12-week-old SHR.These pharmacological findings suggest that in superior mesenteric arteries of the rat, the reduction in EDH-type relaxation occurs with aging and that such a reduction is exacerbated in hypertension.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong Hong Kong SAR, China.

ABSTRACT
Aging is accompanied by endothelial dysfunction due to reduced bioavailability of nitric oxide (NO) and/or reduced endothelium-dependent hyperpolarizations (EDH). This study examines the hypothesis that hypertension aggravates the impairment of EDH-type relaxation due to aging. EDH-type relaxations were studied in superior mesenteric arteries isolated from Wistar Kyoto (WKY) and spontaneously hypertensive (SHR) rats of 12, 36, 60, and 72 weeks of age. EDH-type relaxations in WKY were reduced with aging, and this was associated with an impairment of the function of small-conductance calcium-activated potassium channels (SKC a) and sodium-potassium ATPase (Na-K ATPase). EDH-type relaxation in SHR was smaller than that in WKY arteries, and further reduction occurred with aging. Pharmacological experiments suggested a reduced involvement of SKC a and Na-K ATPase and activation of adenosine monophosphate-activated protein kinase and silent information regulator T1 (sirtuin-1; SIRT1) in mesenteric arteries of 12-week-old SHR. These pharmacological findings suggest that in superior mesenteric arteries of the rat, the reduction in EDH-type relaxation occurs with aging and that such a reduction is exacerbated in hypertension. The latter exacerbation appears to involve proteins associated with the process of cellular senescence and is related to impaired function of SKC a and Na-K ATPase, a phenomenon that is also observed in mesenteric arteries of older normotensive rats.

No MeSH data available.


Related in: MedlinePlus