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Hypergravity exposure decreases γ‐aminobutyric acid immunoreactivity in axon terminals contacting pyramidal cells in the rat somatosensory cortex: A quantitative immunocytochemical image analysis
Author(s) -
D'Amelio Fernando,
Wu LiChun,
Fox Robert A.,
Daunton Nancy G.,
Corcoran Meryl L.,
Polyakov Igor
Publication year - 1998
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/(sici)1097-4547(19980715)53:2<135::aid-jnr2>3.0.co;2-8
Subject(s) - somatosensory system , gabaergic , neuroscience , hypergravity , axon , gamma aminobutyric acid , sensory system , immunocytochemistry , cortex (anatomy) , pyramidal tracts , chemistry , motor cortex , barrel cortex , biology , anatomy , receptor , medicine , endocrinology , stimulation , biochemistry , inhibitory postsynaptic potential
Abstract Quantitative evaluation of γ‐aminobutyric acid immunoreactivity (GABA‐IR) in the hindlimb representation of the rat somatosensory cortex after 14 days of exposure to hypergravity (hyper‐G) was conducted by using computer‐assisted image processing. The area of GABA‐IR axosomatic terminals apposed to pyramidal cells of cortical layer V was reduced in rats exposed to hyper‐G compared with control rats, which were exposed either to rotation alone or to vivarium conditions. Based on previous immunocytochemical and behavioral studies, we suggest that this reduction is due to changes in sensory feedback information from muscle receptors. Consequently, priorities for muscle recruitment are altered at the cortical level, and a new pattern of muscle activity is thus generated. It is proposed that the reduction observed in GABA‐IR of the terminal area around pyramidal neurons is the immunocytochemical expression of changes in the activity of GABAergic cells that participate in reprogramming motor outputs to achieve effective movement control in response to alterations in the afferent information. J. Neurosci. Res. 53:135–142, 1998. © 1998 Wiley‐Liss, Inc.