Temporal analysis of increases in c-fos, preprodynorphin and preproenkephalin mRNAs in rat spinal cord.

Peripheral inflammation produces a rapid elevation (within 4 h) in preprodynorphin mRNA in neurons of the dorsal spinal cord and an even more rapid elevation in c-fos proto-oncogene mRNA (within 30 min). During this period a relatively modest increase is also observed in spinal cord preproenkephalin mRNA. Previous anatomical studies have shown that the neurons in which these transcripts increase have overlapping distributions. Assuming that these events occur in the same cells, it suggests the possibility that newly synthesized c-fos protein may participate in transcriptional regulation of opioid genes in spinal cord.