MONOAMINE-CONTAINING NEURONS IN CENTRAL NERVOUS SYSTEM AND PERIPHERAL NERVES OF LEECH, HIRUDO MEDICINALIS

The 34 ganglia of the leech (Hirudo medicinalis) central nervous system together with their connectives and roots have been studied by means of the fluorescence histochemical technique for monoamines. More than half the ganglia of the central nervous system possess the same number of monoamine‐containing neurons in a fixed location. These identical ganglia consist of seven yellow fluorescent monoamine‐containing neuron perikarya located within the ganglia and a pair of blue‐green fluorescent monoamine‐containing perikarya located outside the ganglia in the anterior roots. A neuropile consisting of a dense network of yellow and blue‐green fluorescent varicose processes, several smooth blue‐green fluorescent processes and occasional smooth yellow fluorescent processes is present in the ganglia. Smooth and varicose yellow and blue‐green fluorescent processes are found in the connectives and roots of the ganglia. The intraneuronal distribution of fluorescence within the nine monoamine‐containing neurons of identical ganglia is described. The monoamine‐containing neurons of the remaining ganglia of the central nervous system are described. These ganglia are shown to vary only slightly from the pattern of identical ganglia. Copyright © 1969 The Wistar Institute of Anatomy and Biology