Induction of c-jun expression in vagal motoneurones following axotomy

Using in situ hybridization, we have measured c-jun mRNA expression in the caudal medulla oblongata of the rat following sectioning of the cervical vagus nerve. Twenty four hours after either unilateral cervical vagotomy or nodose ganglionectomy, motoneurones in the ipsilateral dorsal motor nucleus of the vagus and nucleus ambiguus expressed increased (2-3 fold) levels of c-jun mRNA. After 7 days, c-jun mRNA expression was further elevated to levels 8-10-fold higher than basal. These results demonstrate an unusual, long-lasting activation of a member of the 'leucine zipper' class of immediate early gene, and suggest that immediate early genes such as c-jun may be responsible for the regulation of the expression of structural protein and neuropeptide genes that have been demonstrated to occur following nerve injury.