The discrete anatomical localization of vagal aortic afferents within a catecholamine-containing cell group in the nucleus solitarius.

The centripetal transport of horseradish peroxidase (HRP) was used to visualize the central projections of afferent fibers of the aortic arch nerve to the nucleus solitarius in pigeons. Our results indicate that aortic nerve afferents have a restricted distribution within one subdivision of the nucleus solitarius, designated the subnucleus sulcalis dorsalis. Histofluorescence studies revealed that the aortic nerve projection area is extremely rich in catecholamine-containing neurons.