Ultrastructural evidence for alterations of pituicytes in reanimated rats in connection with experimentally induced clinical death.
This work was undertaken to elucidate some ischaemic and postischaemic changes appearing in the neurohypophysial pituicytes of rats which underwent the incident of clinical death. The incident was experimentally induced by compression of the vascular bundle of the heart for 2.5 min. The ultrastructural organization of pituicytes was investigated directly after reanimation and 3 days after surviving the clinical death. These studies provided evidence for numerous alterations in pituicytes indicating a high sensitivity of the cells to the ischaemic conditions. Thus, four varieties of pituicytes were revealed based on their ultrastructural characteristic, namely: "swollen", "dark", "vacuolated" and "intermediate". Except for the "intermediate" pituicytes (abounding in liposomes), embedding of neurosecretory axons in pituicytes was commonly observed, and thus, several phases of axon degeneration due to pituicytes were noted, including disintegrated axolemma and appearance of a peculiar arrangement of microtubules. These findings strongly support the hypothesis of neuronal-glial interaction in the neurohypophysis under physiological and/or pathophysiological conditions. Thus, the results of the present study are discussed in terms of pituicytes involvement in the mechanisms of control (restriction) of neurohypophysial hormones release in reanimated rats.
Loesch
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Laboratory of the Ultrastructure of the Nervous System, Polish Academy of Sciences, Warsaw.
D000818:Animals; D001369:Axons / Q000648:ultrastructure*; D002545:Brain Ischemia / Q000473:pathology*; D003594:Cytoplasmic Granules / Q000648:ultrastructure; D006323:Heart Arrest / Q000473:pathology; D008297:Male; D008854:Microscopy, Electron; D010904:Pituitary Gland, Posterior / Q000473:pathology*; D051381:Rats; D011919:Rats, Inbred Strains; D012151:Resuscitation; D014617:Vacuoles / Q000648:ultrastructure