Chemical induction of LTP (chemLTP)

ChemLTP was conducted as previously described (Lu et al. 2001). Following vehicle or NYX‐2925 treatment (30 min), cells were washed and placed into chemLTP buffer (in mM: 140 NaCl, 33 glucose, 25 HEPES, and 2 CaCl₂; in μM: 200 glycine, 25 bicuculline, 1 TTX, and 1 strychnine) for 3 min at 37°C prior to being placed in recovery buffer for 20 min (in mM: 140 NaCl, 33 glucose, 25 HEPES, and 2 CaCl₂; in μM: 25 bicuculline, 1 TTX, and 1 strychnine) at 37°C. The chemLTP vehicle cohort was placed into recovery buffer twice instead of chemLTP buffer followed by recovery buffer. Next, cells were washed (cold PBS) and fixed on ice (4% p‐formaldehyde, 4% sucrose, in PBS) for 13 min prior to blocking (10% donkey serum, Sigma‐Aldrich, Cat #: D9663) and incubation with rabbit primary antisera for GluA1 (1 : 10, 1 h, 4°C, Millipore, RRID: AB‐564636) as described (Ohashi et al. 2016), and cy3‐labelled secondary (Jackson ImmunoResearch, West Grove, PA, USA, RRID: AB_2307443). Immunocytochemistry for PSD‐95 and MAP2 proceeded as described above.