Increased spinal cord dynorphin mRNA during peripheral inflammation.

Injection of a complete Freunds adjuvant-saline emulsion into the hindpaw of the rat induces a peripheral inflammatory process accompanied by pronounced increase (3 fold) in spinal cord dynorphin content. A marked increase (approximately 9 fold) in the mRNA coding for the preprodynorphin precursor accompanies the increase in peptide. The parallel elevations of the mRNA and peptide product suggest that an increased activity of dynorphin neurons occurs in spinal cord in response to altered afferent input due to the peripheral inflammatory process.