Dopaminergic and non-dopaminergic projections to amygdala from substantia nigra and ventral tegmental area.

The projections from the substantia nigra (SN) and ventral tegmental area (VTA) to the amygdala of the rat were examined by simultaneous visualization of catecholamine (CA) histofluorescence and retrograde tracer. CA-containing cells in lateral VTA, medial SN and the dorsal edge of SN pars compacta were labeled by injections of propidium iodide (PI) into the amygdala. While CA-containing cells were present in SN pars lateralis (SNl), those cells which were labeled by injections into the amygdala did not contain CA. There is, thus, a significant non-DA projection from SNl to the amygdala.