Territories of heterologous inputs onto Purkinje cell dendrites are segregated by mGluR1-dependent parallel fiber synapse elimination

2015 Fiscal Year Final Research Report

• Project/Area Number: 24500413
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Nerve anatomy/Neuropathology
• Research Institution: Sapporo Medical University
• Principal Investigator: Ichikawa Ryoichi 札幌医科大学, 医学部, 講師 (10223091)
• Project Period (FY): 2012-04-01 – 2016-03-31
• Keywords: シナプス / プルキンエ細胞 / 平行線維 / 登上線維 / 樹状突起 / mGluR1 / PKCg

Outline of Final Research Achievements

In the Purkinje cells (PCs) of the cerebellum, a single “winner” climbing fiber (CF) monopolizes proximal dendrites, while hundreds of thousands of parallel fibers (PFs) innervate distal dendrites, and both inputs innervate a narrow intermediate domain. Through reconstruction of dendritic innervation by serial electron microcopy, we show that from postnatal day 9 to 15 in mice, both territories vigorously expand because of an enlargement of the region of overlapping innervation. From postnatal day 15 onwards, segregation of these input territories occurs by robust shortening of the overlapping proximal region. Thus, innervation territories by heterologous inputs are refined during the early postnatal period. Intriguingly, this phase transition is arrested in mutant mice lacking the type 1 metabotropic glutamate receptor (mGluR1) or protein kinase Cg(PKCg), resulting in the persistence of an abnormally expanded overlapping region.

Free Research Field

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