| Project/Area Number |
15592147
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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 |
Surgical dentistry
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| Research Institution | Osaka Dental College |
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Principal Investigator |
MOMOTA Yoshihiro Osaka Dental College, Dentistry, Lecturer, 歯学部, 講師 (60247880)
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| Co-Investigator(Kenkyū-buntansha) |
KOTANI Junichiro Osaka Dental College, Dentistry, Professor, 歯学部, 教授 (40109327)
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| Project Period (FY) |
2003 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 2004: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2003: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Keywords | regional cerebral blood flow / hyperventilation / hyperventilation syndrome / microspheres / 頻呼吸 / マイクロソフェアー |
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| Research Abstract |
An experimental study using the non-radioactive colored microsphere method was conducted to evaluate changes in regional cerebral blood flow associated with hyperventilation in rabbits. Rabbits underwent controlled ventilation using a mixture of nitrous oxide (67%) and oxygen (33%), and were subjected to the following procedures : (1)PaCO_2 of 30-40 mmHg was obtained by adjusting ventilation frequency and tidal volume and yellow microspheres were then injected into the left atrium (normocapnia group) ; and (2)hyperventilation was induced by increasing ventilation frequency and tidal volume to achieve a PaCO_2 of 25-30 mmHg and blue microspheres were then injected into the left atrium (hypocapnia group). Rabbits were randomly allocated to two groups, one undergoing first the hypocapnia and then the normocapnia procedure and the other undergoing first the normocapnia and then the hypocapnia procedure. Following the procedures, the brain was isolated and microspheres were retrieved from tissue samples from the pons, thalamus, cerebellum, hippocampus, and cerebral cortex as well as blood samples for reference. Blood flow in each sample was calculated on the basis of absorption of microspheres, and comparison of blood flow between normocapnic and hypocapnic procedures was performed. Regional cerebral blood flow in the state of hypocapnia was significantly lower in the cerebral cortex and cerebellum than in the state of normocapnia, but the magnitude of hypocapnia-associated decrease in blood flow was small in the hippocampus, pons, and thalamus. These findings indicate that the decrease in cerebral blood flow due to hyperventilation is especially significant in areas such as the cerebral cortex and cerebellum that require abundant supply of oxygen and to which delivery of blood from cerebral vessels is especially large.
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