Kainate-evoked modulation of gene expression in rat brain.

Kainate is a glutamate analog that produces neuronal excitation resulting in seizures within hours following its intraperitoneal injection into adult rats. Then, at 2-3 days after the treatment, neurodegeneration of apoptotic character can be observed in limbic system. As a consequence, plastic reorganization and glial reactivation phenomena occur. These physiological and pathological responses are reflected by specific changes in gene expression, that can be dissected according to their spatio-temporal patterns. The early phase of gene expression observed in all hippocampal subfields appears to reflect a sudden burst of spiking activity. Changes in mRNA levels restricted to dentate gyrus are suggestive of a link to neuronal plasticity. The late gene expression response implies its correlation either to neuronal cell death or glial reactivation, depending on cellular localization of gene products. Thus analysis of the temporal and spatial gene expression pattern in the hippocampus after kainate treatment may provide clues revealing specific phenomena to which gene expression could be attributed.