Anatomical distribution and ultrastructural organization of the GABAergic system in the rat spinal cord. An immunocytochemical study using anti-GABA antibodies.
gamma-Aminobutyric acid (GABA)-containing elements have been studied by light and electron microscopy in the rat spinal cord, using immunocytochemistry with anti-GABA antibodies. Light microscopy showed immunoreactive somata localized principally in laminae I-III, and occasionally in the deeper laminae of the dorsal horn and in the ventral horn. Small somata were also observed around the central canal. Punctate GABA-immunoreactive profiles were particularly concentrated in laminae I-III, and moderately abundant in the deeper laminae and in the ventral horn where they were observed surrounding the unlabelled motoneurons. At the ultrastructural level, the punctate profiles corresponded to GABA-containing axonal varicosities or small dendrites. GABA-immunoreactive varicosities were presynaptic to labelled or unlabelled dendrites and cell bodies. Some unlabelled terminals presynaptic to unlabelled dendrites received symmetrical synaptic contacts from GABA-immunoreactive terminals. These results confirm data obtained with L-glutamate decarboxylase immunocytochemistry, and support the role of GABA in pre- and postsynaptic inhibition in the spinal cord, respectively via axoaxonal and axosomatic or axodendritic synapses.
Magoul
R
R
Onteniente
B
B
Geffard
M
M
Calas
A
A
D000818:Animals; D000906:Antibodies; D006651:Histocytochemistry; D007124:Immunoenzyme Techniques; D008297:Male; D008854:Microscopy, Electron; D051381:Rats; D011919:Rats, Inbred Strains; D013116:Spinal Cord / Q000032:analysis* / Q000648:ultrastructure; D013569:Synapses / Q000032:analysis / Q000648:ultrastructure; D005680:gamma-Aminobutyric Acid / Q000032:analysis* / Q000276:immunology
D000906:Antibodies; D005680:gamma-Aminobutyric Acid