| Project/Area Number |
11671726
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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 |
Ophthalmology
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| Research Institution | Tokyo Medical and Dental University |
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Principal Investigator |
KIYOSAWA Motohiro Tokyo Med & Dent Univ. Graduate School. Dept of Visual Science and Ophthalmology, Tokyo Medical and Dental University, Associate Professor, 大学院・医歯学総合研究科, 助教授 (20169957)
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| Co-Investigator(Kenkyū-buntansha) |
MORI Hiroshi Tokyo Med & Dent Univ. Graduate School. Dept of Visual Science and Ophthalmology, Tokyo Medical and Dental University, Assistant (Jyosyu), 医学部・附属病院, 助手 (50302849)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2000: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1999: ¥2,900,000 (Direct Cost: ¥2,900,000)
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| Keywords | Period of Sceptibility / rat / enucleation / Visual Cortex / glucose metabolism / receptor density / autoradiogram / neural plasticity / 化塑性 / ウイスターラット / 瞼裂縫合 / 外側膝状体 / アデノシンA1 / 糖代謝率 |
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| Research Abstract |
PURPOSE.To study the changes in adenosine A1 and benzodiazepine receptors and glucose metabolism in the visual structures of rats following monocular deprivation by enucleation and eyelid suture at postnatal day 10.
METHODS.The right eye of rats were deprived by enucleation or eyelid suture and ex vivo autoradiography of the brain was performed at different times up to 45 days after the treatment. [1-methyl-1 1C]8-dicyclopropylmethyl-1-methyl-3-propylxanthine ([11C]MPDX) and [11C]flumazenil were used to map adenosine A1 receptors and benzodiazepine, respectively, and glucose metabolism was evaluated with [14C]2-deoxyglucose, and. The receptor-specific binding for 11C activity and the uptake of 14C activity in the superior colliculus (SC), visual cortex (VC) and dorsal lateral geniculate body (DLG) were determined.
RESULTS.The specific binding of [11C]MPDX to the adenosine A1 receptors in the contralateral SC significantly decreased immediately after enucleation and remained low thereafte
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r, whereas the specific binding of [11C]flumazenil to benzodiazepine receptors in the contralateral SC increased after 5 days. The uptake of [14C]2-deoxyglucose in the SC was depressed only one day after enucleation and then returned to the ipsilateral level. No significant difference between contralateral and ipsilateral sides was found in any other visual structures at any time investigated for the all three tracers. On the other hand, after the eyelid suture all three tracers showed symmetrical images without any detectable changes.
CONCLUSIONS.The axon degeneration related a decrease of the adenosine A1 receptor density resulted in an upregulation of postsynaptic benzodiazepine receptor density in monoculaely enucleated, not in eyelid sutured, rats at PN 10. Neither visual deprivation methods induced alteration in both receptors nor in glucose metabolism in any visual structures, except that the glucose metabolism was decreased only in the contralateral SC one day after the enucleation. These results suggest that the benzodiazepine receptors are susceptible to degeneration of presynaptic nerve terminals, but not to visual deprivation, and that the visual functions are not determined in rats at PN 10. Less
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