Journal of Neuroscience, Vol 1, 241-249, Copyright © 1981 by Society for Neuroscience
Decreased glutamate uptake in subcortical areas deafferented by sensorimotor cortical ablation in the cat
AB Young, MB Bromberg and JB Penney Jr
Evidence that L-glutamate is a neurotransmitter of corticofugal fibers was
sought by measuring changes in several biochemical markers of
neurotransmitter function after pericruciate (sensorimotor) ablations in
cats. Two weeks after cortical ablation, samples from various brain regions
were analyzed for high affinity uptake of glutamate, gama- aminobutyric
acid (GABA), glycine, alanine, and tyrosine. Amino acid levels and the
activity of choline acetyltransferase (CAT) also were determined. High
affinity glutamate uptake is decreased relative to the opposite side in
areas of the nervous system which lost a predominantly unilateral
corticofugal projection. These areas include the caudate nucleus,
ventrolateral thalamic nucleus, red nucleus, basis pontis, and cervical and
lumbar spinal cord. No significant changes were found in the uptake of
other amino acids or in CAT in these regions. Changes in the levels of
amino acids were significant only in ventrolateral thalamus where there was
a 33% decrease in glutamate on the deafferented side. The data suggest that
L-glutamate is a neurotransmitter of corticofugal fibers to many
subcortical areas related to motor control.