The Washington University Institutional Animal Care and Use Committee approved all protocols for animal experiments according to NIH guidelines. Using methods described previously, hippocampal slices were prepared from postnatal day 28–32 Harlan (Indianapolis, IN) Sprague-Dawley male albino rats (Tokuda et al., 2010, 2011). For slice preparation, rats were anesthetized with isoflurane, and dissected hippocampi were pinned at their ventral pole on an agar base in ice-cold artificial cerebrospinal fluid (ACSF) that contained (in millimolars) 124 NaCl, 5 KCl, 2 MgSO4, 2 CaCl2, 1.25 NaH2PO4, 22 NaHCO3, and 10 glucose, bubbled with 95% O2 and 5% CO2 at 4–6°C. The dorsal two-thirds of the hippocampus was cut into 500-µm slices using a rotary tissue slicer and kept in a chamber with gassed ACSF at 30°C for at least 1 hour before use in physiology studies.