Increased Fos induction in adult rats that experienced neonatal peripheralinflammation

The response to noxious stimulation was compared in adult rats that had per ipheral inflammation as neonates and untreated rats. On postnatal day 1, ra t pups experienced complete Freund's adjuvant (CFA)-induced inflammation of the left hind paw. At 8 weeks of age, these rats and neonatal untreated ra ts received a bilateral injection of CFA into their hind paws. Fos-like imm unoreactivity (Fos-LI) was used as a measure of neuronal activity in dorsal horn nociceptive pathways. A significant increase in Fos-LI was found on t he left side of the lumbar spinal cord of neonatal treated rats as compared to neonatal untreated rats. These results suggest that the experience of n eonatal peripheral inflammation may result in an increase in the response o f spinal cord neurons to peripheral inflammation as adults. NeuroReport 12: 925-927 (C) 2001 Lippincott Williams & Wilkins.