Ultrastructure of the neuropil of the brain oculomotor nuclei was studied in mice after 30-day exposure to microgravity on Bion-M1 biosatellite and after 13-h exposure to Earth gravity. The number of axo-dendritic synapses in the neuropil of the oculomotor nucleus significantly decreased after the flight. Degenerated axon terminals containing conglomerates of presynaptic vesicles appeared. The number of synapses with high functional activity increased and the length of active zones of the axo-dendritic synapses significantly increased. The observed ultrastructural changes of the neuropil of the oculomotor nuclei of mice exposed to microgravity reflect the development of long-term deafferentation of the analyzed brain structures. These changes in the neuropil ultrastructure can determine the disturbances in the oculomotor system, e.g. development of atypical nystagmus under conditions of microgravity.
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Andreev-Andrievsky AA, Shenkman BS, Popova AS, Dolguikh ON, Anokhin KV, Soldatov PE, Ilyin EA, Sychev VN. Experimental studies with mice on the program of the biosatellite Bion-M1 mission. Aviakosm. Ekol. Med. 2014;48(1):14-27. Russian.
D’iachkova LN. Ultrastructural changes in somatosensory cortex of albino rats during space flight. Izv. Akad. Nauk. Ser Biol. 2007;(3):372-5.
Kornilova LN, Kozlovskaya IB. Neurosensory Mechanisms of Space Adaptation Syndrome. Fiziol. Chel. 2003;29(5):17-28. Russian.
Krasnov IB, Diachkova LN. Morphology of the rats’ brain in and after space flight: ultrastructure of the livor. Aviakosm. Ekol. Med. 2003;37(1):18-24. Russian.
Shtanchayev RSh, Mikheyeva IB, Pen’kova NA, Pavlik LL. Ultrastructure of motor neurons and synapses in the oculomotor nerve nuclei in mice. Morfologiya. 2015;147(2):21-25. Russian.
Berning S, Willig KI, Steffens H, Dibaj P, Hell SW. Nanoscopy in a living mouse brain. Science 2012;335:551.
Büttner-Ennever JA. The extraocular motor nuclei: organization and functional neuroanatomy. Prog. Brain Res. 2006;151:95-125.
Krasnov IB. Gravitational neuromorphology. Adv. Space Biol. Med. 1994;4:85-110.
Nguyen LT, Baker R, Spencer RF. Abducens internuclear and ascending tract of Deiters inputs to medial rectus motoneurons in the cat oculomotor nucleus: synaptic organization. J. Comp. Neurol. 1999;405(2):141-159.
Paxinos G, Franklin K. The Mouse Brain in Stereotaxic Coordinates. San Liego, 2012.
Sekirnjak C, du Lac S. Physiological and anatomical properties of mouse medial vestibular nucleus neurons projecting to the oculomotor nucleus. J. Neurophysiol. 2006;95(5):3012-3023.
Shiraki K, Miyazaki S, Shimo-oku M. Influence of visual deprivation on the visual and oculomotor system: acetylcholinesterase activity in oculomotor neurons. Exp. Neurol. 1988;99(2):342-352.
Waxman SG, Pappas GD. Ultrastructure of synapses and cellular relationships in the oculomotor nucleus of the rhesus monkey. Cell Tissue Res. 1979;204(2):161-169.
Wentzel PR, De Zeeuw CI, Holstege JC, Gerrits NM. Inhibitory synaptic inputs to the oculomotor nucleus from vestibulo-ocular-reflex-related nuclei in the rabbit. Neuroscience 1995;65(1):161-174.
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Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 165, No. 4, pp. 447-451, April, 2018
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Mikheeva, I.B., Shtanchaev, R.S., Pen’kova, N.A. et al. Structure of Interneuronal Contacts in the Neuropil of the Oculomotor Nuclei in Mouse Brain under Conditions of Long-Term Microgravity. Bull Exp Biol Med 165, 457–460 (2018). https://doi.org/10.1007/s10517-018-4193-8
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DOI: https://doi.org/10.1007/s10517-018-4193-8