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Space flight affects magnocellular supraoptic neurons of young prepuberal rats: transient and permanent effectsEffects of microgravity on postural control and volume of extracellular fluids as well as stress associated with space flight may affect the function of hypothalamic neurosecretory neurons. Since environmental modifications in young animals may result in permanent alterations in neuroendocrine function, the present study was designed to determine the effect of a space flight on oxytocinergic and vasopressinergic magnocellular hypothalamic neurons of prepuberal rats. Fifteen-day-old Sprague-Dawley female rats were flown aboard the Space Shuttle Columbia (STS-90, Neurolab mission, experiment 150) for 16 days. Age-matched litters remained on the ground in cages similar to those of the flight animals. Six animals from each group were killed on the day of landing and eight animals from each group were maintained under standard vivarium conditions and killed 18 weeks after landing. Several signs of enhanced transcriptional and biosynthetic activity were observed in magnocellular supraoptic neurons of flight animals on the day of landing compared to control animals. These include increased c-Fos expression, larger nucleoli and cytoplasm, and higher volume occupied in the neuronal perikaryon by mitochondriae, endoplasmic reticulum, Golgi apparatus, lysosomes and cytoplasmic inclusions known as nematosomes. In contrast, the volume occupied by neurosecretory vesicles in the supraoptic neuronal perikarya was significantly decreased in flight rats. This decrease was associated with a significant decrease in oxytocin and vasopressin immunoreactive levels, suggestive of an increased hormonal release. Vasopressin levels, cytoplasmic volume and c-Fos expression returned to control levels by 18 weeks after landing. These reversible effects were probably associated to osmotic stimuli resulting from modifications in the volume and distribution of extracellular fluids and plasma during flight and landing. However, oxytocin levels were still reduced at 18 weeks after landing in flight animals compared to controls. This indicates that space flight during prepuberal age may induce irreversible modifications in the regulation of oxytocinergic neurons, which in turn may result in permanent endocrine and behavioral impairments.
Document ID
20040088691
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Garcia-Ovejero, D.
(Instituto Cajal, C.S.I.C., Avda. Doctor Arce 37, E-28002 Madrid, Spain)
Trejo, J. L.
Ciriza, I.
Walton, K. D.
Garcia-Segura, L. M.
Date Acquired
August 21, 2013
Publication Date
October 24, 2001
Publication Information
Publication: Brain research. Developmental brain research
Volume: 130
Issue: 2
ISSN: 0165-3806
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: NS33467
Distribution Limits
Public
Copyright
Other
Keywords
NASA Experiment Number 9301150
short duration
NASA Discipline Neuroscience
Non-NASA Center
manned
STS-90 Shuttle Project
Flight Experiment

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