Ej. Vanbockstaele et Vm. Pickel, GABA-CONTAINING NEURONS IN THE VENTRAL TEGMENTAL AREA PROJECT TO THE NUCLEUS-ACCUMBENS IN RAT-BRAIN, Brain research, 682(1-2), 1995, pp. 215-221
The ventral tegmental area receives a gamma-aminobutyric acid (GABA) i
nnervation from the nucleus accumbens and contains GABA immunoreactive
neurons believed to be interneurons. We combined the immunocytochemic
al detection of retrogradely transported Fluoro-Gold (FG) from the nuc
leus accumbens (Acb) with the detection of GABA within the same sectio
n of tissue in the ventral tegmental area (VTA) of the rat brain to de
termine whether there might also be reciprocal GABAergic projections i
n the mesolimbic pathway. Immunoperoxidase labeling for FG and immunog
old-silver labeling for GABA were most readily distinguished within pe
rikarya and dendrites in sections examined by electron microscopy. Ult
rastructural observations indicated that 36% (n = 110) of the FG-label
ed perikarya and dendrites also contained GABA immunoreactivity. The p
resent results provide the first evidence that GABA is contained in a
subpopulation of neurons in the mesolimbic pathway from the VTA to the
Acb. The reciprocity of this circuitry may provide an important feedb
ack loop thus facilitating inhibition of motor activity.