Growth associated protein-43 mRNA expression in nucleus ambiguus motoneurons after recurrent laryngeal nerve injury in the rat.

OBJECTIVE

To investigate the time-dependent differences in growth associated protein-43 (GAP-43) mRNA expression in the nucleus ambiguus (NA) motoneurons after recurrent laryngeal nerve (RLN) transection in the rat.

MATERIAL AND

METHODS

Animals were sacrificed on Days 1, 7, 14 and 21 after axotomy. The sections were then processed for in situ hybridization of GAP-43 mRNA.

RESULTS

GAP-43 mRNA transiently increased after axotomy, reaching a peak on postoperative Day 7, and then decreased gradually at 14 and 21 days after axotomy. The peak period of GAP-43 expression in the NA is different from those in the facial and hypoglossal nuclei after axotomy.

CONCLUSION

We have already reported that neuronal nitric oxide synthase (nNOS) is induced in the NA motoneurons after axotomy and reaches a peak on postoperative Day 14. This study shows that the expressions of GAP-43 and nNOS are chronologically different.