GAP-43 mRNA Expression in Facial Motoneurons During Regeneration: In situ Hybridization Histochemistry Study Using an Alkaline Phosphatase-labelled Probe

Abstract

By means of in situ hybridization histochemistry using an alkaline phosphatase-labelled probe, we found an increase of mRNA for the growth-associated protein GAP-43 in rat facial motoneurons following axotomy of the facial nerve. After nerve resection, the increased level of GAP-43 mRNA was maintained for at least 8 weeks, while it returned to almost undetectable levels by 8 weeks after nerve crush injury. Thus, expression of GAP-43 mRNA in motor neurons paralleled the process of axonal regeneration. However, the increase of GAP-43 mRNA after resection was more pronounced than after crushing, in this way being different from the pattern of low-affinity nerve growth factor receptor mRNA expression.

Key Words:

• growth cone
• motor neuron
• B-50
• F1
• facial nucleus
• rat.