[7 types of neurons in the substantia nigra of the rat. Golgi rapid-impregnation study].

The substantia nigra of the adult rat was investigated by means of the Golgi rapid impregnation technique. Seven neuron types could be distinguished which differ with respect to morphological features (size and shape of pericaryon and dendritic pattern), behaviour of axons and prevalent localization within the nuclear area: 1. Polygonal neurons with somatic spines 2. Polygonal neurons without somatic spines 3. Fusiform neurons 4. Trigonal neurons 5. Small spherical neurons 6. Small spindle-shaped neurons 7. Neuroglioform neurons. The neuron types 1-4 are considered to represent nigral projection neurons; the types 5-7 might be interneurons. The findings presented here are discussed in view of recent physiological and biochemical as well as behavioral-pharmacological results.