Effect of a discrete dorsal forebrain lesion in the rat on the expression of neuronal and glial-specific genes: induction of calmodulin, NF-L, SC1, and GFAP mRNA.

The influence of a localized tissue injury on the expression of genes encoding specific neuronal and glial proteins was examined using in situ hybridization. A pronounced induction of neuron-specific calmodulin (CaM) mRNA was evident within cells proximal to the wound site by 2 hours following a cortical lesion in rats. By 12 hours postlesion, intense signal corresponding to CaM mRNA was found to extend 1 mm from the wound site. Changes in the expression of mRNA encoding two additional neuronal proteins, the 68 kilodalton neurofilament protein and the extracellular matrix protein, SC1, were also evident at 12 hours following the cortical injury. Of the two glial proteins examined, a dramatic elevation in levels of mRNA for glial fibrillary acidic protein (GFAP) was observed at the wound site by 12 hours postlesion. This intense labeling corresponding to GFAP mRNA was evident in the ipsilateral glial limitans and hippocampus as well as in the contralateral glial limitans. In contrast, the pattern of labeling for the beta-subunit of the S100 protein did not differ from that of control animals at either of the postlesion intervals examined. This study identifies four genes, CaM, GFAP, SC1, and NF-L, which are induced following a localized cortical injury and which encode mRNA species enriched in specific cell-types in the central nervous system.