Is there a dopaminergic projection from the A11 catecholamine cell group to the amygdala?

The dopaminergic nature of the pathway from the subparafascicular thalamic nucleus and its adjacent region to the amygdala was reexamined by means of retrograde fluorescent tracers coupled with tyrosine hydroxylase (TH) immunofluorescence. After injecting a small amount of tracer into the amygdala, retrogradely labeled cells were found in the subparafascicular thalamic nucleus and its adjacent periventricular region. TH immunofluorescence showed that these labeled cells completely lacked TH immunoreactivity. Similar results were obtained when a larger amount of tracer was applied to the amygdala. The present study, in contrast to the previous report describing the dopaminergic innervation of the amygdala by the cells in and around the subparafascicular area (A11 catecholamine cell group), indicates that the A11 cell group does not contribute to a dopaminergic input to the amygdala.