Abstract
This paper reviews the organization of the cardiovascular control neurons in the central nervous system (CNS). Above all, the rostral ventrolateral medulla (RVLM) is the most important relay station in these neurons.
A topological difference in cardiovascular neurons in the brain stem was found between those projecting to the cardioacceleratory center in the intermediolateral nucleus (IML) of the T2 segment and those projecting to the vasomotor center in the IML of the T11 segment. This was determined by the retrograde transport of WGA-HRP to and the immunoreactive response to glutamate and GABA in the supraspinal CNS of rats. These findings indicate that : 1. The glutamatergic projections, from the RVLM and the A5 area, to the lower thoracic vasomotor center were more frequent than those to the upper thoracic cardioacceleratory center. 2. The glutamatergic and GABAergic projections from the caudal ventrolateral medulla to the upper thoracic cardioacceleratory center were more frequent than those to the lower thoracic vasomotor center. 3. In the RVLM, there was no viscerotopic distribution of the glutamatergic neurons between those projecting to the upper thoracic cardioacceleratory center and those projecting to the lower thoracic vasomotor center.
