The ultrastructural morphology and cytochemistry of the neurosecretory system of the old rat after experimentally evoked clinical death.

In this study we examined the changes in the neurosecretory system of the old rat after the incident of clinical death. Using the method of Korpaczew et al., (1982) we developed 10 minutes long period of clinical death, followed by resuscitation by indirect heart massage and controlled lung ventilation. The material for the morphological and cytochemical examinations (supraoptic and paraventricular nuclei, neurohypophysis) were sampled 10 months after the experiment was initiated. Two types of ultrastructural changes in the neurosecretory system of the experimental animals were shown: the typical ischaemic changes and, secondly, the pattern characteristic for the processes of senescence. Both types of lesions were responsible for irreversible damage of some tissue elements (neurons, glial cells) of the neurosecretory system. To present these alterations we performed the cytochemical studies using the pyroantimonate method as described by Mata et al., (1987). Moreover, in this paper we discuss the role of microglia as an element participating in the regulation of the neurosecretory system, especially stressing its potential for effective phagocytosis.