GABAergic vesicle-containing dendrites and spines: a critical element in processing sensory input in the monkey...

Antibodies directed against gamma-aminobutyric acid (GABA) were used to immunostain monkey lumbar spinal cord. In laminae I and II, ultrastructural analysis demonstrated GABA-immunoreactive (-IR) vesicle-containing dendrites as well as the more commonly emphasized immunoreactive cell bodies and terminals. Spines were a consistent feature of these dendrites, and some of the spines contained synaptic vesicles. GABA-IR dendrites were observed postsynaptic to large glomerular-type terminals, small-diameter axon terminals and other vesicle-containing dendrites. They were presynaptic to dendritic shafts and spines. These data suggest that GABA-IR dendrites and dendritic spines may play an important role not only as receptive elements but also provide a means for transferring information from neuron to neuron.