Distribution of glycinergic terminals on lumbar motoneurons of the adult cat: an ultrastructural study.
The distribution of glycine-like immunoreactivity on cat lumbar motoneurons was examined in electron microscopy, using pre-embedding immunocytochemistry. In the dorsolateral portion of the ventral horn, numerous labeled axon terminals were presynaptic to somatic and dendritic profiles of alpha-motoneurons. Most of the glycinergic boutons contained pleomorphic vesicles and showed symmetrical contacts. On the somatic and proximal dendritic compartments, glycinergic terminals accounted for, respectively, 24.6 and 26.6% of the total number of terminals. There were very few glycinergic terminals on gamma-motoneurons. Immunoreactive axons, dendrites and cell bodies were also observed near the motoneurons. These results support the view that glycine plays a major role in the inhibition of alpha-motoneurons and suggest that inhibitory mechanisms occur on the soma as well as on dendrites.
Destombes
J
J
URA CNRS 1448, Laboratoire de Neurophysiologie, Collège de France, Paris.
Horcholle-Bossavit
G
G
Thiesson
D
D
D000818:Animals; D002415:Cats; D005998:Glycine / Q000032:analysis*; D007124:Immunoenzyme Techniques; D008161:Lumbosacral Region; D008854:Microscopy, Electron; D009046:Motor Neurons / Q000737:chemistry* / Q000648:ultrastructure; D009411:Nerve Endings / Q000737:chemistry* / Q000648:ultrastructure
D005998:Glycine