Netrin G-2 ligand mRNA is downregulated in spinal motoneurons after sciatic nerve lesion.

Netrin G-2 ligand (NGL-2) and synaptic adhesion like molecules induce synapses in vitro. We investigated the expression of these molecules in a model of CNS synaptic detachment and restoration in vivo. After axotomy of spinal motoneurons, synapses are lost from the somata of lesioned motoneurons. We could not detect any synaptic adhesion like molecule mRNA in the spinal cord, but signal for NGL-2 mRNA was seen in motoneurons. The signal for NGL-2 decreased after sciatic nerve transection and sciatic nerve crush. After regeneration, the levels of NGL-2 mRNA were partially restored after sciatic nerve transection, but completely restored after sciatic nerve crush. We conclude that axotomized motoneurons decrease their NGL-2 expression and that the restoration of NGL-2 expression mirrors the restoration of synaptic inputs.