The nucleus of the solitary tract (NTS) is one of the major targets for visceral afferents to the central nervous system. Within the NTS, norepinephrine (NE) neurons of the A2 group are located within the medial and commissural subnuclei, areas that are densely innervated by the vagus nerve. We reported last year that the NE innervation of the midbrain dopamine (DA) cell areas largely originates in the A1 and A2 neurons (Mejias-Aponte et al., SfN 2004, 465.4). This was of interest as visceral (e.g., food-related) inputs to these DA cells may be involved in reward processing. Here, we extend those studies by examining ascending projections of A2 area neurons to the retrorubral area of A8 DA neurons. Immunostaining for dopamine beta-hydroxylase showed a high density of adrenergic fibers among A8 DA neurons. A less dense, but similar, pattern of fibers was also found for the epinephrine marker, phenylethanolamine N-methyl transferase, indicating that NE is the major adrenergic neurotransmitter. Retrograde lab...