Aberrant glutamate receptor 5 expression in temporal lobe epilepsy lesions

Glutamate receptor 5 (GluR5) plays a role as an excitatory regulator of synaptic transmission and plasticity; however, its exact role in the pathological mechanism underlying epilepsy is not fully known. We investigated GluR5 expression in resected brain tissues from humans with temporal lobe epilepsy (TLE) and from a macaque model of Coriaria lactone-induced TLE. GluR5 was upregulated in the hippocampus, but not in the temporal neocortex, of patients with TLE compared to the control group. In contrast, GluR5 expression in the hippocampus of macaques treated with Coriaria lactone was not upregulated compared to the control. In addition, mossy fiber sprouting in the hippocampus of TLE patients was correlated with GluR5 upregulation, whereas mossy fiber sprouting was not observed in the macaque model lacking GluR5 upregulation, suggesting that GluR5 function is mainly associated with mossy fiber sprouting.