Morphologic evidence of a primary response of gila to kainic acid administration into the rat neostriatum; studied in vivo and in vitro.
Glial changes that follow kainic acid administration were studied in the rat neostriatum at many different time intervals after the lesion, both in the animal model of Huntington's chorea and in an organotypic culture of striatum. The glial reaction showed striking similarities between in vivo and in vitro conditions and resulted in extensive production and accumulation of gliofilaments leading to transformation of the protoplasmic type of astroglia into the fibrous type. The earliest ultrastructural study in vivo revealed severe swelling of the astrocytic cytoplasm and additional morphologic changes of cytoplasmic organelles, i.e., enlargement of mitochondria, dilation of rough endoplasmic reticulum, and presence of numerous vacuoles. The glial pathology progressed parallel to neuronal degeneration. The same reaction was observed in culture both in the explanted tissue in which neurons remained intact and in the distant outgrowth zone containing a pure population of glial cells. This study proved that kainic acid might act directly on astroglia cells and that glial changes were independent of neuronal damage. Because kainic acid is a structural analog of glutamate, the presented results may be interpreted to reflect changes in the metabolism of this amino acid occurring in astroglia independently of neuronal changes. This interpretation is consistent with the existence of two independent metabolic compartments of glutamate.
D000818:Animals; D001253:Astrocytes / Q000187:drug effects / Q000648:ultrastructure; D003342:Corpus Striatum / Q000187:drug effects* / Q000473:pathology / Q000648:ultrastructure; D003470:Culture Media; D006816:Huntington Disease / Q000473:pathology; D007267:Injections; D007608:Kainic Acid / Q000494:pharmacology*; D008854:Microscopy, Electron; D009457:Neuroglia / Q000187:drug effects* / Q000473:pathology / Q000648:ultrastructure; D009924:Organ Culture Techniques; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors
D003470:Culture Media; D007608:Kainic Acid