1991 Fiscal Year Final Research Report Summary
Studies on regulating factors of cerebral blood flow during cerebral ischemia
| Project/Area Number |
01570042
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
General physiology
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| Research Institution | Yamanashi Medical College |
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Principal Investigator |
TAKEUCHI Toru Dept. of Physiol., Yamanashi Medical College, Professor, 医学部, 教授 (00020727)
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| Co-Investigator(Kenkyū-buntansha) |
HORIUCHI Jouji Dept. of Physiol., Yamanashi Medical College, Instructor, 医学部, 助手 (40181523)
TERADA Nobuyuki Dept. of Physiol., Yamanashi Medical College, Instructor, 医学部, 助手 (90155466)
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| Project Period (FY) |
1989 – 1991
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| Keywords | Parietal cortex tissue blood flow / Systemic arterical pressure / Hypoxic, hyperoxic and hypercapnic loadings / Renal nerve activity / Vasomotor center activating factor / Blood flow in rostral ventrolateral medulla / Tissue PO_2, PCO_2, pH in rostral ventrolateral medulla / 腎神経活動 |
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| Research Abstract |
1. Even when the blood supply to the rabbit brain was restricted to a sole route of the internal carotid artery on one side, the parietal cortex tissue blood flow(CTF)kept 97% of the control value.
2. The relationship between systemic arterial pressure(SAP)and CTF was described by a linear regression equation.
3. The magnitude of increase in tissue PCO_2 in the rostral ventrolateral medulla(RVLM)during complete interruption of blood supply to the brain for one minute equalled that of increase in the tissue PCO_2 in RVLM during inhalation of 2% CO_2 air mixture.
4.5% CO_2 air mixture inhalation increased significantly tissue PCO_2 in the RVLM and decreased significantly interstitial pH, and also increased significantly blood flow in the RVLM, renal nervous activity(RNA)and SAP. The 5% CO_2 loading influenced nothing on the increasing patterns of RNA and SAP caused by graded cerebral ischemia.
5.8% O_2 and 90% O_2 gas mixture inhalations induced respectively significant decrease and increase in tissue PO_2 in the RVLM. The 8% O_2 loading increased significantly blood flow in the RVLM. The 8% O_2 loading and 90% O_2 loading induced respectively marked increase and strong attenuation in both RNA and SAP rises caused by cerebral ischemia. The results obtained by multiple linear regression analysis indicated that severe hypoxia was the main factor activating the vasomotor center in the RVLM when the RVLM was exposed to ischemia.
6. Blood vessels in the RVLM were dilated strongly by cerebral ischemia and thus the blood vessels in the RVLM during cerebral ischemia did not respond significantly to hypoxic and hypercapnic loadings.
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