Temporal and spatial preferences of c-fos mRNA expression in the rat brain following cortical lesion

Abstract

The expression of the proto-oncogene c-fos is increased in neuronal cells by a number of stimuli and the usefulness of this gene as a marker of neuronal activity has been demonstrated. The temporal and spatial expression of c-fos mRNA following the induction of unilateral cortical lesion have been investigated in the rat brain by Northern blot analysis and in situ hybridization histochemistry. It was observed that the lesion evoked a rapid increase (20-fold) in the content of c-fos mRNA in the ipsilateral cortex, whereas in the contralateral cortex c-fos mRNA expression was more modest (7-fold). In the whole hippocampus a large and very rapid increase (17-fold) of c-fos mRNA expression was detected. The effects of a cortical lesion on Ca2+ uptake membrane potential was also investigated. Using synaptosomes as a model system, we have provided evidence that Ca2+ entry via membrane depolarization increases in coordination with c-fos gene expression in neuronal cells. The principal conclusions from this study are that cortical lesion induce transient expression of the c-fos gene in specific neuronal cells of the rat brain. © 1993.