Electroconvulsive Seizure-induced Gene Expression Profile of the Hippocampus Dentate Gyrus Granule Cell Layer

Electroconvulsive shock (ECS) is the most effective treatment for depression, but the mechanism underlying the therapeutic action of this treatment is still unknown. To better understand the molecular changes that may be necessary for the clinical effectiveness of ECS we have combined the technologies of gene expression profiling using cDNA microarrays with T7-based RNA amplification and laser microdissection to identify regulated genes in the dentate gyrus granule cell layer of the hippocampus. We have identified genes previously reported to be up-regulated following ECS, including brain-derived neurotrophic factor, neuropeptide Y, and thyrotrophin releasing hormone, as well as several novel genes. Notably, we have identified additional genes that are known to be involved in neuroprotection, such as growth arrest DNA damage inducible beta (Gadd45beta), and the excitatory amino acid transporter-1 (EAAC1/Slc1A1). In addition, via in situ hybridization we show that EAAC1 is specifically up-regulated in the dentate gyrus, but not in other hippocampal subfields. This study demonstrates the utility of microarray analysis of microdissected subregions of limbic brain regions and identifies novel ECS-regulated genes.