Aim: 

The biomolecular responses of primary sensory neurons to partial or total peripheral axotomy have been widely investigated. However, the effects of central deafferentation on intact sensory neurons need to be further analyzed. This study was aimed at investigating the biomolecular responses of trigeminal ganglia neurons following cortico-trigeminal path degeneration induced by left ablation of MI-MII face areas.

Methods: 

The expression of the early genes c-fos and c-jun, GAP-43, a major protein of axonal growth cones, and alpha tyr-tubulin (tyr-tub), a marker of dynamic microtubules, was analyzed by Western Blot in the right and left ganglia of adult rats.

Results: 

The c-fos and c-jun were significantly up-regulated in the right ganglia in comparison with the contralaterals and the respective controls. By contrast, a gradual significant increase of the protoncogenes expression was detected at the 2^nd, 7^th and 15^th days after a central trigeminal deafferentation. The tyr-tub expression remained unchanged at the 2^nd and 7^th day, while it increased significantly at the 15^th . Finally, no significant variation of GAP-43 expression was pointed out. Results showed that the c-fos and c-jun up-regulation preceded that of GAP-43 and tyr-tub, linked with later phenomena of neosynaptogenesis and sprouting.

Conclusion: 

Therefore, rather than play an exclusive role in encoding axonal reparative processes, these protoncogenes may be involved as well as in the plastic responses of primary neurons to deafferentation.