1993 Fiscal Year Final Research Report Summary
Quatitation of Neurotransmission using Positron Emission, Tomography : Aging Effects and Changes in Dementia Patients.
| Project/Area Number |
04836003
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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 |
老化(加齢)
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
ITOH Masatoshi Tohoku Univ., CYRIC, Associate Progessor, サイクロトロン・ラジオアイソトープセンター, 助教授 (00125501)
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| Co-Investigator(Kenkyū-buntansha) |
MEGURO Kenichi Tohoku Univ., CYRIC, Resertch Associate, 医学部・付属病院, 助手 (90239559)
FUJIWARA Takehiko Tohoku Univ., CYRIC, Resertch Associate, サイクロトロン・ラジオアイソトープセンター, 助手 (70238632)
IDO Tatsuo Tohoku Univ., CYRIC, Progessor, サイクロトロン・ラジオアイソトープセンター, 教授 (80134063)
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| Project Period (FY) |
1992 – 1993
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| Keywords | DOPAMINE / POSITRON TOMOGRAPHY / NEUROTRANSMISSION / DEMENTIA / AGING / D2 RECEPTOR |
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| Research Abstract |
A study was initiated to analyze the central neurotransmission mainly of dopamine system of 27 subjects including AD/SDAT snd vascular dementia of multi-infarct type using positron emission tomography(PET). 18F-labeled fluoro-L-dopa(FDOPA) and 11C-labeled YM09151-2(YM), aD2 receptor ligand were successfully labeled in our institution. Sequential PET data collection. was performed using PT931, CTI inc, Knoxville, U.S.A.to recotd tracer accumulation to the striatum. A semi-automated ROI draw routine was developed to identify the striatum that interactively defined the boundary pixels defined on the histogram curves and images simultaneously. The graphical plot was employed to calculate FDOPA influx rate(Ki) for the ROI data using cerebellar radioactivity as input function. The D2 receptor concentration was estimated by uptade ratio of the YM to the striatum and to the cerebellum. The Ki values were found relatively stable and did not show significant age-related chages. The correlation analysis between Ki and severity of dementia as assessed by mini-mental scale revealed significant reduction of Ki associated with the progression of dementia severity. The D2 receptor density was increased in accordance with receptor supersensitivity related to the reduced presynaptic stimuli. This uncoupling between uptake of a tracer by presynaptic neurons and postsynaptic receptors was most noted in vascular patient, where as AD/SDAT patients showed variable trends which may relate to heterogenous origin of this category. We concludes imaging of neurotransmission with positron emission tomography can be a new diagnostic modality to assess nueronal function of individual neurotransmission system in vivo and in humam.
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