Novel method for the labeling of distant neuromuscular junctions

Essential to understanding the roles proteins and structural elements play at the synapse is to understand the development, remodeling and reinnervati on of peripheral neuromuscular junctions. It has, however, been a challengi ng task to label and visualize neuromuscular junctions, in this paper we de monstrate how adenovirus technology can be combined with intraspinal microi njection techniques to follow both the development and the reinnervation of a distant peripheral neuromuscular junction in the rat. A recombinant aden ovirus containing VAMP-2 (synaptobrevin-2) was fused to the green fluoresce nt protein (GFP) and microinjected into the region of the lumbar motor neur ons. We were able to follow the neuronal incorporation, axonal transport an d synaptic localization of the GFP-VAMP-2 using fluorescence microscopy. GF P-VAMP-2 was found in neuronal cell bodies, selected sciatic nerve axons an d was concentrated in the presynaptic nerve terminal. During reinnervation of the neuromuscular junction, GFP-VAMP-2 allows us to follow the time cour se of junctional reinnervation. Thus, the microinjection of microliter amou nts of labeled recombinant virus into locations far distant from target reg ions can be used to efficiently study the formation of neuromuscular juncti ons with a minimum of trauma to the animal. J. Neurosci. Res. 61.61-66, 200 0. (C) 2000 Wiley-Liss, Inc.