The Journal of Neuroscience, April 1, 2002, 22(7):2617-2625
Rapid, Experience-Dependent Changes in Levels of Synaptic Zinc in
Primary Somatosensory Cortex of the Adult Mouse
Craig E.
Brown and
Richard H.
Dyck
Department of Psychology, University of Calgary, Calgary, Alberta,
Canada T2N IN4
Electrophysiological studies have established that the adult
cerebral cortex undergoes immediate functional reorganizations after
perturbations of the sensory periphery. These activity-dependent modifications are thought to be mediated via the rapid regulation of
the synaptic strength of existing connections. Recent studies have
implicated synaptic zinc as contributing to activity-dependent mechanisms of cortical plasticity, such as long-term potentiation and
long-term depression, by virtue of its potent ability to modulate glutamatergic neurotransmission. To investigate the role of synaptic zinc in cortical plasticity, we examined changes in the barrel-specific distribution of zinc in axon terminals innervating the primary somatosensory cortex of adult mice at different time points after whisker plucking. In layer IV of normal adult mice, zinc staining in
the barrel field was characterized by intense staining in inter-barrel septae and low levels of staining in barrel hollows. Within 3 hr, and
up to 1 week after the removal of a row of whiskers, zinc staining
increased significantly in barrel hollows corresponding to the plucked
whiskers. With longer survival times, levels of zinc staining gradually
declined in deprived barrel hollows, returning to normal levels by 2-3
weeks after whisker removal. Increased levels of zinc staining in
deprived barrel hollows were highly, negatively correlated with the
length of whiskers as they regrew. These results indicate that levels
of synaptic zinc in the neocortex are rapidly regulated by changes in
sensory experience and suggest that zinc may participate in the plastic
changes that normally occur in the cortex on a moment-to-moment basis.
Key words:
zinc; experience-dependent plasticity; somatosensory
cortex; whiskers; adult; mouse
Copyright © 2002 Society for Neuroscience 0270-6474/02/2272617-09$05.00/0
Previous Article | Next Article
