1989 Fiscal Year Final Research Report Summary
Regulation of cerebral blood flows by cholinergic fibers originating in the nucleus basalis of Meynert.
| Project/Area Number |
63480102
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
General physiology
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| Research Institution | Tokyo Metropolitan Institute of Gerontology |
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Principal Investigator |
SATO Akio Tokyo Metropolitan Institute of Gerontology, Department of Physiology, Director., 生理学部, 部長 (60072980)
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| Co-Investigator(Kenkyū-buntansha) |
INANAMI Osamu Tokyo Metropolitan Institute of Gerontology, Department of Physiology, Researche, 生理学部, 研究員 (10193559)
SATO Yuko Tokyo Metropolitan Institute of Gerontology, Department of Physiology, Senior Re, 生理学部, 主任研究員 (10072985)
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| Project Period (FY) |
1988 – 1989
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| Keywords | cerebral cortical blood flow / nucleus basalis of Meynert / regional cerebral blood flow / electrical stimulation / septo-hippocampal system / anesthetized rat / cholinergic fiber |
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| Research Abstract |
Intracerebral cholinergic fibers originating in the nucleus basalis of Meynert (NBM) and septum, and projecting to the cortex and hippocampus, respectively, have been reported to degenerate in Alzheimer's disease as well as in aged people. However, physiological function of these cholinergic fibers have remained obscure. The present experiment was performed to examine whether these fibers can act as vasodilators in the cortex and hippocampus using anesthetized rats. Regional cerebral blood flow was measured by either laser Doppler flowmetry or ^<14>C iodoantipirine technique. The unilateral NBM or medial septum was stimulated electrically or chemically. Stimulations of the NBM and medial septum produced increases in cortical and hippocampal cerebral blood flows, respectively.
But, cerebral blood flows in other regions did not change significantly during these stimulations. These vasodilative responses were reduced by intravenous administrations of muscarinic and nicotinic blocking agents (atropine, 0.5 mg/kg, and mecamylaminel 2 mg/kg). The extracellular acetylcholine in the cortex and hippocampus measured by the microdialysis technique was increased significantly during stimulations of the NBM and medial septum. In conclusion, activation of the intracerebral cholinergic fibers releases acetylcholine in the cortex and hippocampus, and at least some parts of the released acetylcholine result in vasodilation and increase in these regional cerebral blood flows. At this moment I would like to speculate by analogy of this system to the peripheral sympathetic cholinergic vasodilative system in skeletal muscles which activates and supplies sufficient oxygen and glucose to skeletal muscles, just before they start to contract, with a preparatory purpose.
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