OBJECTIVETo explore the effect of up-regulation of KA1 subunit of the kainate receptor on endoplasmic reticulum stress (ERS)-induced excitotoxic neurodegeneration in mouse hippocampus.

METHODSSeventy adult male KM mice were subjected to microinjections into the hippocampus of kainic acid (KA) or 500, 1000, or 2000 µg/ml tunicamycin (TM). At 1, 2, 3, 4, 5, 8, and 12 h after the injections, the mice were assessed for Bederson scores and sacrificed for FJB staining and immunofluorescence observation of the brain slices.

RESULTSAt 3, 4, 5, and 8 h after KA injection and at 4 and 5 h after of 2000 µg/ml TM injection, the mice showed severe central nervous system dysfunction, and FJB staining revealed increased cell death in the hippocampus, where up-regulated expressions of KA1 receptor and ERS marker P-eIF2α were found by immunofluorescence staining (P<0.05).

CONCLUSIONMicroinjection of KA or TM into the hippocampus causes neuronal death and ERS with up-regulated expression of KA1. In this process of neuronal apoptosis, the membrane receptor KA1 receives the apoptosis signal and transfers it to the inside of the cells to cause cell endoplasmic reticulum dysfunction and ERS response, which ultimately leads to neuronal death.