| Co-Investigator(Kenkyū-buntansha) |
NAGANO Takashi Fukui Medical University, School of Medicine, Assistant Professor, 医学部, 助手 (70272854)
SATO Makoto Fukui Medical University, School of Medicine, Professor, 医学部, 教授 (10222019)
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| Budget Amount *help |
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 2000: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1999: ¥2,800,000 (Direct Cost: ¥2,800,000)
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| Research Abstract |
Myelin-associated glycoprotein (MAG), one of the membrane proteins of the immunoglobulin-gene super family provides a clue regarding the inhibition of axonal regeneration. Following transection of peripheral nerves, abundant sprouts and young axons are pruned away at the same time that MAG is released from the distal end of a transected nerve (Torigoe et al., 1998). In the central nervous system, however, neither release of MAG nor inhibition of axonal regeneration has been obvious in vivo. In the present study, the optic nerve segments in mice are maintained at the popliteal fossa for 3 to 16 days. Axons were degenerated and cleaned from the nerve segments, while the denervated glia were proliferated, being gliosis from the 10th day after axotomy. The predegenerated nerve segments are positioned close to the freshly cut end of the common peroneal nerves, sandwiched between two sheets of thin plastic film, and maintained in vivo for 4 days. The regenerated axons are visualized on the f
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ilm with silver impregnation. There were neither regenerating axons nor sprouts in a parent nerve, using the predegenerated nerve segments subjected to axotomy 10 to 16 days earlier. The inhibitory molecules releasing from the predegenerated segments are absorbed in acrylamide gel, transferred by western blotting, and stained by antibodies to MAG.Myelin-associated glycoprotein was detected in the optic nerve segments subjected by axotomy 10 to 16 days earlier. The inhibitory effect on sprouts were completely blocked by local application of anti-MAG antibodies. On the fourth day after being inhibited by the predegenerated nerve segments, the common peroneal nerve are transected proximally to a cutting point of the first axotomy. Regenerating axons elongated on the surface of film, meaning that the inhibitory effect by MAG is not a central response, but a local one near a connecting region of MAG with neuron receptors. Now, MAG is analyzed by the molecular orbital calculations as well as acrylamide which is LUMO functionally in the intoxication. Less
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