EFFECTS OF STAPHYLOCOCCAL ALPHA-TOXIN ON THE ULTRASTRUCTURE OF THE RAT HYPOTHALAMONEUROHYPOPHYSEAL SYSTEM

The influence of staphylococcal a-toxin on the ultrastructure of hypot halama-neurohypophysical system in the brain (nucleus supraopticus, nu cleus paraventricularis, neurohypophysis) was studied in the rat. In n eurohypophysis, an area lacking blood-brain barrier, alpha-toxin damag ed both neuronal endings and capillary vessels. On the other hand in h ypothalamus, where blood-brain barrier is present structural alteratio ns were much less pronounced, Reactive gliosis, accordant with cell da mage, was observed in the entire neurosecretory system. Putative mecha nisms leading to brain damage after systemic administration of a-toxin , including direct disruption of cell membrane and induction of nitric oxide synthesis, are discussed.