[Electron microscopy analysis of the structural elements of the vestibular input to nodulus Purkinje's cells in rats exposed to a 9-day space flight].
Electron microscopy was used to study structural elements of the vestibular afferent input to the cerebellar nodulus Purkinje's cells--terminals of mossy fibers and granular cells in the granular layer and parallel fibers and Purkinje's cell dendrites in the molecular layer in rats decapitated in 2-3 hours and 9 days after the 9-day space flight aboard NASA shuttle Columbia (STS 40, SLS-1 mission). Analysis of the revealed ultrastructural changes on the base of morphofunctional correlations leads to the following conclusions: 1) space flight induced a prolonged reduction in vestibular input to most of the mossy fiber terminals and nodulus Purkinje's cells; 2) within the initial hours of recovery the vestibular input to a part of mossy fiber terminals and granular cells was increasing due to elevation of the sensitivity of vestibular receptors in microgravity; 3) regain of the vestibular input to Purkinje's cells after space flight is hampered by structural, as a result of microgravity effects, and also functional, developing shortly after space flight, impediments, and 4) in 9 d after landing the vestibular input to Purkinje's cells was almost normal. The observed reduction in the vestibular input to the nodulus Purkinje's cells during and after the spaceflight microgravity is presumably the key to the mechanism altering the velocity storage in mammals in microgravity and on return from space flight.
Krasnov
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D000818:Animals; D003712:Dendrites / Q000648:ultrastructure*; D005500:Follow-Up Studies; D008297:Male; D008854:Microscopy, Electron / Q000379:methods*; D009475:Neurons, Afferent / Q000648:ultrastructure*; D011689:Purkinje Cells / Q000648:ultrastructure*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013026:Space Flight; D013997:Time Factors; D014725:Vestibular Nerve / Q000648:ultrastructure*; D014893:Weightlessness / Q000009:adverse effects