Immunocytochemical approach of GABAergic innervation of the mouse spinal cord using antibodies to GABA

The distribution of gamma-amino-butyric acid containing neurons in the Mouse spinal cord has been studied at both the light and electron microscope levels using antibodies against GABA and revelation by the Fab-peroxidase technique. At the light microscope level immunoreactive profiles of perikarya and neuronal processes were particularly abundant in the superficial laminae (I-IV) of the dorsal horn. Scattered soma profiles were found in the other layers and more particularly in the lamina X where Liquor contacting immuno-reactive neurons could be detected. GABAergic cell bodies were very sparse in the ventral horn. Electron microscopic observations confirmed the light microscope results: terminals constituted synaptic symmetrical contacts that provide a morphological basis for inhibition in the dorsal horn and for post-synaptic inhibition of motoneurons in the ventral horn.