Cell type selective expression of a slow AMPA/kainate EPSC in hippocampal interneurons

This study investigated how kainate receptors (KARs) are targeted to hippocampal interneuron synapses in CA1. Interneurons in stratum radiatum/lacunosum‑moleculare expressed somatodendritic KARs with and without GluR5, but only GluR5‑containing KARs contributed to synaptic EPSCs. AMPA receptors also generated a slow EPSC tail current, which did not appear in spontaneous events, suggesting receptor segregation across synapses. The slow tail reflected intrinsic AMPAR kinetics rather than glutamate spillover. In stratum oriens interneurons, GluR5‑KARs were extrasynaptic and did not contribute to EPSCs. Findings indicate cell‑type, synapse‑specific, and subunit‑dependent KAR localization.