LABILE STORES OF MONOAMINES IN THE CENTRAL NERVOUS SYSTEM: A HISTOCHEMICAL STUDY

¹ Department of Pharmacology, University of Pennsylvania Schools of Medicine, Philadelphia, Pennsylvania

The distribution of tissue monoamines in cat and rat central nervous systems has been studied by histochemical techniques. Samples of the brain taken from living anesthetized animals showed that monoamines were present in cells of the substantia nigra, and in fibers of the cortex, hippocampus, lateral geniculate boly, spinal cord, hypothalamus and caudate nucleus. In brain samples from previously killed animals, monoamines were only present in the hypothalamus and caudate nucleus. This suggests the presence of a labile store of monoamines with a more widespread distribution than has hitherto been described. The functional implications of this widespread distribution are discussed.