Journal of Neuroscience, Vol 6, 2864-2874, Copyright © 1986 by Society for Neuroscience
Sprouting of GABAergic synapses in the red nucleus after lesions of the nucleus interpositus in the cat
H Katsumaru, F Murakami, JY Wu and N Tsukahara
An immunocytochemical study using anti-GAD serum was performed to examine
the plastic changes of GABAergic inhibitory synapses in the red nucleus
(RN) after lesions of the nucleus interpositus (IP) of the cat.
Light-microscopic analyses revealed that 20-175 d after the unilateral
lesion of the IP, somatic profiles of large neurons in the magnocellular RN
contralateral to the lesion were more densely covered with
GAD-immunoreactive puncta than those in the ipsilateral RN.
Electron-microscopic analyses demonstrated that the GAD-immunoreactive
puncta observed with the light microscope were synaptic terminals and that
the number of GAD-immunoreactive synaptic terminals per unit length of
somatic membrane of RN neurons was increased on the deafferented side. The
GAD-immunoreactive terminals on somata of RN neurons made symmetric
synaptic contacts with somatic membranes on both the deafferented and
control sides. The number of immunoreactive synapses on somata of RN
neurons was markedly increased on the deafferented side following IP
lesion, whereas that of the unlabeled asymmetric synapses was decreased.
These observations indicate that new GABAergic synapses were formed on
somata of RN neurons after deafferentation from the IP.