Electroshock seizures protect against apoptotic hippocampal cell death induced by adrenalectomy

Seizures evoked by electroshock induce rapid changes in the expression of s everal genes in the adult brain, including those encoding for neurotrophic factors, Some of the neurotrophic factors induced by brief seizures such as basic fibroblast growth factor and nerve growth factor have been shown to have neuroprotective action. We reasoned therefore that these seizures may protect against neural injury. To test this hypothesis, we examined the eff ect of electroshock-induced seizures on the vulnerability to cell death in the hippocampus. Cell death was induced by adrenalectomy, which results in a highly selective apoptotic neuronal death in the dentate granule cell lay er of the hippocampus. Daily electroshock seizures were administered for se ven days to sham-operated and adrenalectomized rats. Neuronal degeneration was evaluated by the highly sensitive and reliable cupric-silver impregnati on method. Animals experiencing electroshock seizures were completely prote cted against adrenalectomy-induced cell death, whereas adrenalectomized ani mals not exposed to electroshock seizures exhibited substantial neuronal ce ll degeneration in the dentate granule cell layer. Daily restraint stress d id not prevent the adrenalectomy-induced neuronal death, indicating that th e neuroprotective effect of the seizure treatment is not accounted for by s tress. We conclude that brief controlled seizure-evoked neural activation may allo w the sparing of otherwise vulnerable neuronal populations in the injured a dult brain. This prompts a need to explore the possibility that controlled administration of electroshock seizures may have therapeutic potential in t reating neurodegenerative disorders. (C) 1999 IBRO. Published by Elsevier S cience Ltd.