Journal of Neuroscience, Vol 2, 681-686, Copyright © 1982 by Society for Neuroscience
Cell size changes in the lateral geniculate nuclei of normal and monocularly deprived cats treated with 6-hydroxydopamine and/or norepinephrine
PF Hitchcock and TL Hickey
Given the proposed role of catecholamines in controlling cortical
plasticity in the cat (Kasamatsu, T., J. D. Pettigrew, and M. Ary (1979) J.
Comp. Neurol. 185: 163-182), we were interested in whether evidence of such
control also could be found in the dorsal lateral geniculate nucleus. We
undertook geniculate cell size measurements in 26 normal or monocularly
deprived cats, 23 of which had been used in cortical recording studies
concerned with catecholamine-induced plasticity. For animals grouped
according to experimental treatments, the results can be summarized as
follows: (1) in visually normal animals, neither intraventricular
injections of 6-hydroxydopamine (6- OHDA) nor local perfusions of
norepinephrine (NE) cause changes in geniculate cell size. (2) In otherwise
untreated kittens, 1 week of monocular deprivation begun in the 6th week of
life results in quite obvious changes in geniculate cell size. (3)
Intraventricular injections of 6-OHDA do not appear to prevent
deprivation-induced changes in geniculate cell size. (4) Older NE-treated
kittens and adult cats that are monocularly deprived for a brief period
either late in the critical period or after the critical period has ended
do not show deprivation-induced changes in geniculate cell size in either
hemisphere. (5) In younger kittens which had been first injected with 6-
OHDA intraventricularly and then monocularly deprived for a brief period
early in the critical period, there is no evidence to suggest that a local
perfusion of NE enhances deprivation-induced changes in geniculate cell
size.