| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2006: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2005: ¥2,500,000 (Direct Cost: ¥2,500,000)
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| Research Abstract |
Cerebellar Purkinje cell (PC) receives only two types of excitatory input, parallel fibers (PFs) and climbing fibers (CFs), whose terminals were segregated distributed onto PC dendrites, PFs at distal portion and CFs at proximal portion. The competition between PF and CF to extend synaptic territory onto PC dendrite has been generally accepted to play important role to generate the unique synaptic organization. In this study, we tried to disclose the mechanism of competition between PF and CF to form synapse on the spines from PC dendrite, at adult age and developing period.
First, to examine the competition mechanism at adult age, under the curcumstances of the damage of PFs or CFs or both PFs and CFs we observed synaptic wiring on PC. After PFs were damaged, following transient emergence of free spines the survived PFs exclusively formed synapses at distal portion of PC dendrite. After CFs were damaged, PF synpases were newly formed at proximal protion, however, spine density per dedritic length was unchnaged and proportion of PF synapses was under 20%. After both PF and CF were damaged, free spines persisted on entirely PC dendrite, and spine density was increased at proximal portion, moreover proprtion of PF synpases was over 40 % at proximal portion. These results indicate that PFs or CFs have the tendency to maintain the completed synaptic orgainzation to support counterpart input to form proper synpases after the damage of conterpart. Second, to examin the mechanism at. developing period, we observed synaptic organization of PC, after partially damaged granule cell (origin of PFs) at P0 or after damaged CFs at P7, when CFs halting around cell somata. Now we are analising the images.
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