Regulation of excitability of smooth muscle by endothelium in cerebral arterioles -Intercellular humoral and electrical signal transduction-
| Project/Area Number |
13670108
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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 |
General pharmacology
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| Research Institution | Fukuoka Dental College |
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Principal Investigator |
YAMAZAKI Jun Fukuoka Dental College, Faculty of Dentistry, Associate Professor, 歯学部, 助教授 (50230397)
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| Project Period (FY) |
2001 – 2002
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| Project Status |
Completed (Fiscal Year 2002)
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| Budget Amount *help |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 2002: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 2001: ¥2,200,000 (Direct Cost: ¥2,200,000)
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| Keywords | smooth muscle / endothelium / nitric oxide / gap junction / chloride current / arteriole / patch-clamp / electrophysiology / コンダクタンス / 対称性 / コネキシン / エンドセリン / Cl^-電流 |
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| Research Abstract |
In the present research project, I attended to investigate regulation of smooth muscle cells (SMCs) by endothelium (EC) via cell-to-dell humoral and electrical communication, using arterioles dissected from the rat cerebral pial membrane. 1. By means of the perforated whole-cell patch-clamp technique, a hyperpolarizing voltage step applied to SMC in voltage-clamp mode elicited the inward current through the SMC membrane as well as the outward current through EC membrane (gap-junctional current), which was attenuated by α-glycyrrhetinic acid (α-GA). This result suggests the existence of electrical coupling between SMC and EC. 2. To investigate the role of humoral factors, I examined the effect of bradykinin on endothelin-1 (ET-1)-evoked oscillatory Ca2+-activated Cl- currents (I_<Cl(Ca)>) under the condition where junctional current was abolished by α-GA. As a result, bradykinin was shown to release nitric oxide to an extracellular space, and to inhibit an ET-1-evoked I_<Cl(Ca)> in smooth muscle cells. 3. Gap junction was demonstrated to exist between adjacent SMCs. The junctional current declined time-dependently. This phenomenon was voltage-dependent, and symmetrical for the positive and negative junctional voltages. On the other hand, the junctional current between SMC and EC exerted asymmetrical voltage-dependency. Gap-conductance could be estimated according to the macroscopic current measured, series resistance created by the electrodes, and assumption that gap-resistance among the surrounded cells should be connected in parallel. Single-channel conductance could also be calculated under the condition where a gap-junction inhibitor was performed at a modest concentration. All of these techniques are likely to enable to analyze various types of communication between cells of microvasculature with intact structure.
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Report
(3 results)
Research Products
(13 results)
