Distribution of catecholamine‐containing cell bodies in the rabbit central nervous system

A recently developed fluorescence histochemical technique, which both fixes the brain in situ and converts catecholamines to fluorescent derivatives, has been utilised to study the distribution of catecholamine‐conataining cell bodies in the central nervous system of the rabbit, a species particularly suited to cardiovascular investigation. Catecholamine‐conataining cells are widely distributed through the brain stem but are absent from the spinal cord, the cerbellum and the telencephalon. In the medulla the cells form separate ventrolateral and dorsomedial groups, while pontine cells form a continuous gruop, comprising cells of the locus coeruleus, the subcoeruleus and the ventrolateral pontine area. Fluorescent cella are widely distributed in the midbrain including an extensive group in the substantia nigra and a smaller dorsal group in the central gray matter just ventral to the aqueduct. Nearly all fluorescent forebrain cells are found in the hypothalamus, in the arcuate nucleus and in the more caudal reigons of the dorsal hypothalamus. Although the general arragement of the catecholamine‐containing cells is similar to that of the rat there are some readily appreciated differences. Ventrolateral medullary cells are more tightly grouped in the rabbit and dorsomedial medullary cells extend forther rostrally, some being found within the dorsal motor nucleus of the vagus. Locus coeruleus cells are more loosely arranged in the rabbit and the subcoeruleus group is more extensive. Midbrain cells are closely comparable but the caudal thalamic group described in the rat is less extensive in the rabbit.