| Co-Investigator(Kenkyū-buntansha) |
YAMADA Masaru Kitasato Univ. School of Medicine, Research Associate, 医学部, 教授 (90210484)
MIYASAKA Yoshio Kitasato Univ. School of Medicine, Associate Professor, 医学部, 助教授 (90104538)
IRIKURA Katsumi Kitasato Univ. School of Medicine, Assistant Professor, 医学部, 講師 (70176519)
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| Budget Amount *help |
¥2,900,000 (Direct Cost: ¥2,900,000)
Fiscal Year 2001: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2000: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1999: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Research Abstract |
The pathophysiology of the venous ischemia, postulated as the result from increased venous pressure associated with intracerebral arteriovenous malformation, is not well understood. We created the animal model of cerebral venous hypertension at the chronic period in rats by cervical A-V fistularization and determined cerebral blood flow in that model.
(1) animal model of chronic cerebral venous hypertension (VH)
Superior sagittal sinus pressure (SSSP) were 15【minus-plus】4, 5【minus-plus】2 and 5【minus-plus】3 (mmHg, mean【minus-plus】SD) in VH group, vessel occlusion group and sham operated group, respectively. SSSP was significantly elevated m VH group (p<0.05).
(2) absolute regional cerebral blood flow (rCBF) determination by ^<14>C-iodoamphetamme (IMP)
Mean absolute rCBF were 10313, 9016, 7711 (ml/min/100g) in VH group, vessel occlusion group and sham operated group, respectively. The difference among each group were significant. Even after subtraction of the amount of extracerebral IMP assu
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med by usage of ^3H-rat serum albumin (a plasma tracer), rCBF elevated m VH group significantly.
(3) Discussion
In this new model, SSSP elevated singnificantly. We also showed increase in IMP uptake in brain, which seems contrast to clinical experience. The mechanism of IMP uptake into brain includes pH difference between intra- and extra- cellular fluid, and binding to non-specific high volume amine binding site. By plasma tracer study, we excluded the possibility of apparent rCBF increase by increased extracerebral blood volume. In the vessel occlusion group, SSSP was not elevated but rCBF was significantly higher than sham group. Therefore, the mechanism of IMP uptake increase is probably due to increase of first pass extraction of IMP possibly by slow circulation and not by IMP behavior change due to venous hypertention. Change of IMP cerebral blood distribution coefficient after venous hypertension is completely unknown.
(4) Conclusion
We created a new mode, of cerebral venous hypertension and found elevated rCBF in this model. Less
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