[Electron-microscopic characteristics of the dorsomedial nucleus of the brain amygdala].

Dark and light neurons with morphological signs of secretory activity were discovered for the first time in one of the main zones of sexual dimorphism of brain amygdala (dorsomedial nucleus). Dark neurons were of small and medium sizes, contained large nuclei and incompletely developed perikaryon. The latter contained a large number of free ribosomes, dilated cisterns of endoplasmic reticulum, hypertrophied Golgi complex with forming secretory granules and numerous mitochondria. Elementary neurosecretory granules (ENG) 75-180 nm in size were found in light neurosecretory cells that are likely to represent dark neurons at the specific phase of functional activity. Synapses of all known types, containing small light vesicles in their terminals and vesicles with electron-opaque centre and ENG were detected in the extremely active neuropil.