--- res: bibo_abstract: - The rocker mice are hereditary ataxic mutants that carry a point mutation in the gene encoding the CaV2.1 (P/Q-type) Ca2+ channel α1 subunit, and show the mildest symptoms among the reported CaV2.1 mutant mice. We studied the basic characteristics of the rocker mutant Ca2+ channel and their impacts on excitatory synaptic transmission in cerebellar Purkinje cells (PCs). In acutely dissociated PC somas, the rocker mutant channel showed a moderate reduction in Ca2+ channel current density, whereas its kinetics and voltage dependency of gating remained nearly normal. Despite the small changes in channel function, synaptic transmission in the parallel fiber (PF)-PC synapses was severely impaired. The climbing fiber inputs onto PCs showed a moderate impairment but could elicit normal complex spikes. Presynaptic function of the PF-PC synapses, however, was unexpectedly almost normal in terms of paired-pulse facilitation, sensitivity to extracellular Ca2+ concentration and glutamate concentration in synaptic clefts. Electron microscopic analyses including freeze-fracture replica labeling revealed that both the number and density of postsynaptic α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors substantially decreased without gross structural changes of the PF-PC synapses. We also observed an abnormal arborization of PC dendrites in young adult rocker mice (∼ 1 month old). These lines of evidence suggest that even a moderate dysfunction of CaV2.1 Ca2+ channel can cause substantial changes in postsynaptic molecular composition of the PF-PC synapses and dendritic structure of PCs.@eng bibo_authorlist: - foaf_Person: foaf_givenName: Takashi foaf_name: Kodama, Takashi foaf_surname: Kodama - foaf_Person: foaf_givenName: Yuko foaf_name: Itsukaichi-Nishida, Yuko foaf_surname: Itsukaichi Nishida - foaf_Person: foaf_givenName: Yugo foaf_name: Fukazawa, Yugo foaf_surname: Fukazawa - foaf_Person: foaf_givenName: Minoru foaf_name: Wakamori, Minoru foaf_surname: Wakamori - foaf_Person: foaf_givenName: Mariko foaf_name: Miyata, Mariko foaf_surname: Miyata - foaf_Person: foaf_givenName: Elek foaf_name: Molnár, Elek foaf_surname: Molnár - foaf_Person: foaf_givenName: Yasuo foaf_name: Mori, Yasuo foaf_surname: Mori - foaf_Person: foaf_givenName: Ryuichi foaf_name: Ryuichi Shigemoto foaf_surname: Shigemoto foaf_workInfoHomepage: http://www.librecat.org/personId=499F3ABC-F248-11E8-B48F-1D18A9856A87 orcid: 0000-0001-8761-9444 - foaf_Person: foaf_givenName: Keiji foaf_name: Imoto, Keiji foaf_surname: Imoto bibo_doi: 10.1111/j.1460-9568.2006.05191.x bibo_issue: '11' bibo_volume: 24 dct_date: 2006^xs_gYear dct_publisher: Wiley-Blackwell@ dct_title: A CaV2.1 calcium channel mutation rocker reduces the number of postsynaptic AMPA receptors in parallel fiber-Purkinje cell synapses@ ...