UC Irvine

A single electroconvulsive shock (ECS) resulted in a major induction of cerebral ornithine decarboxylase (ODC) mRNA and a rapid and transient elevation of ODC enzyme activity. The proto-oncogene c-fos was also transiently induced under the same conditions. Following a rapid rise in mRNA levels, the messages for these proteins take different courses. The c-fos mRNA fell to below control levels by 1 h, while the ODC mRNA remained elevated beyond 24 h. The ECS-induced elevation of ODC enzyme activity was not abolished by adrenalectomy but was attenuated significantly by the anti-convulsant MK-801. These results imply that the induction of cerebral ODC may be neuronal activity dependent, and suggest that the ODC/polyamine system may be linked to the proposed third messenger cascade, involving c-fos, which couples cell stimulation to gene expression, resulting in long-term adaptive responses.