PENTYLENETETRAZOLE-INDUCED SEIZURES STIMULATE TRANSCRIPTION OF EARLY AND LATE RESPONSE GENES

Cellular immediate early gene and neuropeptide gene expression have ea ch been demonstrated to be modulated in hippocampus in response to a v ariety of seizure-inducing stimuli. In this study, gene transcription for three immediate early genes, c-fos, c-jun and NGFI-A, and three ne uropeptide genes, enkephalin, dynorphin and neuropeptide Y, was invest igated using nuclear run-on assays following a single injection of the convulsant pentylenetetrazole (PTZ). At 15 min following PTZ injectio n, only transcription for c-fos was increased. By 6 h following PTZ tr eatment, transcription for all immediate early genes and for dynorphin and neuropeptide Y was increased; however, this increase was transien t in that transcription of all genes returned to control values by 48 h following PTZ treatment. Thus, regulation of immediate early and neu ropeptide gene mRNA levels and immunoreactivity occurs, at least in pa rt, at the level of transcription for the genes encoding neuropeptide Y, dynorphin, c-fos, c-jun, and NGFI-A. Moreover, the difference betwe en increased transcription rates reported here and increased mRNA leve ls reported here and elsewhere suggests that additional post-transcrip tional regulation of gene expression occurs in hippocampal neurons.