| Project/Area Number |
11670686
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Circulatory organs internal medicine
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| Research Institution | KYUSHU UNIVERSITY |
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Principal Investigator |
OHYA Yusuke University Hospital, KYUSHU UNIVERSITY Assistant Professor, 医学部・附属病院, 助手 (30240964)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 2000: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1999: ¥1,100,000 (Direct Cost: ¥1,100,000)
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| Keywords | hypertension / ion channel / artery / 平滑筋 |
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| Research Abstract |
Our progress during two years (1998-1999) are summarized as follows :
1) Enhanced activation of voltage-operated calcium (Ca) channels in vascular smooth muscle cells from Dahl salt sensitive rats
Dietary salt loading elevates blood pressure in Dahl salt sensitive rats. Arterial smooth muscle cells exhibited depolarized resting membrane potential and spontaneous electrical activity in rats after salt loading. We demonstrated by using the patch clamp method that activation of L-type calcium was enhanced in salt-loaded rats. Enhanced activation was especially evident near the resting potential, suggesting that this mechanism would contribute enhanced electrical activity of arterial tissues.
2) Sodium-potassium (Na-K) pump in vascular smooth muscle cells
Na-K pump regulates intracellular ion concentration and membrane potential. We for the first time characterized Na-K pump of vascular smooth muscle cells by using the patch clamp method. Activation of Na-K pump depended on intracellular Na, extracellular K, temperature, and membrane potential. Sensitivity to ouabain of smooth muscle Na-K pump was high. Inhibition of Na-K pump by ouabain depolarized membrane potential, suggesting that Na-K pump would contribute to regulation of membrane potential in vascular smooth muscle cells.
3) Potassium (K) channels in rat mesenteric arterial smooth muscle
We performed molecular identification of voltage-dependent K channels in smooth muscle of rat mesenteric arteries by immunohistochmistry. At least three components such as Kv1.2, Kv1.5, and Kv2.1 were identified. In patch clamp experiments, voltage dependent K currents were decreased in spontaneously hypertensive rats compared to normotensive control rats, Wistar Kyoto rats.
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