[Electron-microscopic changes in neurosecretory nuclei of the rat hypothalamus after total ischemia in short-term clinical death].

Hypothalamic neurosecretory nuclei of rats in which short-term clinical death was experimentally induced, were examined electron-microscopically. Material for studies was taken two weeks after resuscitation of animals following 5 min cardiac and respiratory arrest. Application of aldehyde fixatives with Alcian blue as well as fixatives containing tannic acid revealed numerous additional ultrastructural features not visualized in routine electron microscopy. The obtained results are indicative that short-term cerebral ischemia in rats results in ultrastructural abnormalities in neurosecretory hypothalamic nuclei, which appear after 2 weeks survival. These are electron microscope exponents of reduced secretory function, increased number of lysosomal structures and changes in cytoskeleton organization. They are accompanied by abnormalities in axoplasm and myelin sheaths. The authors consider those structural abnormalities as exponents of delayed irreversible metabolic changes of nerve cells.