Mice

Wild-type (Charles River Laboratories and Japan SLC) and Cbln1-null mice were used for primary culture. In experiments assessing cerebellar functions, we used male and female Cbln1-null mice with the C57BL/6J or ICR genetic backgrounds and GluD2-null mice (13) with the C57BL/6J genetic background. They were housed on a conventional 12 hours light/dark cycle (light on at 8:30 a.m.) and their behavior was tested in the light phase of the cycle. Mice expressing enhanced green fluorescent protein (EGFP) under the control of a modified Thy1 promoter region (The Jackson Laboratory, cat. no. 007788) were used for immunohistochemistry. In experiments assessing hippocampal functions, we used male C57BL/6J, PV-Cre/Ai9 double transgenic mice (The Jackson Laboratory, cat. no. 017320 and 007909), 5xFAD mice (The Jackson Laboratory, cat. no. 006554) which carry five familial AD mutations, and their wild-type littermates with C57BL/6J genetic background (Charles River Laboratories). At least one week before starting the experiments, mice were transferred from the main animal facility of DZNE (Magdeburg, Germany) to a small vivarium, where they were housed individually with food and water ad libitum before food restriction diet (FRD) was given, on a reversed 12 hours light/dark cycle (light on at 9:00 p.m.). All behavioral experiments assessing hippocampal functions were performed in the late afternoons during the dark phase of the cycle when mice were active, under constant temperature (22° ± 1°C) and humidity (55 ± 5%). For the spinal cord injury (SCI) model, wild-type mice with the ICR genetic background (Japan SLC) were used. They were housed on a conventional 12 hours light/dark cycle. Locomotor functions were assessed at a fixed time in the evening. All treatments and behavioral procedures were conducted in accordance with ethical animal research standards defined by German and Japanese law and approved by the Ethical Committee on Animal Health and Care of the State of Saxony-Anhalt, Germany, with license numbers 42502-2-1343 DZNE and 42502-2-1322 DZNE, by the Animal Resource Committee of Keio University (no. 09050) and by the Institutional Animal Care and Use Committee of Aichi Medical University (no. 1559).