Fluoro-Gold tracing of zinc-containing afferent connections in the mouse visual cortices.
To identify zinc-containing projections to the visual areas, we injected Fluoro-Gold into the occipital cortex of the mouse. Five days later, the mice underwent an intravital selenium-labeling procedure to demonstrate the somata of neurons that give rise to zinc-containing boutons. Numerous double-labeled cells were seen in the ipsi- and contralateral primary (layers II/III and VI), and secondary visual cortices (layers II/III and VI). A few double-labeled cells were apparent in other cortical areas concerned with visual processing: the orbital cortex (layers II and III), the posterior portion of the medial agranular frontal cortex (layer V/VI border), and the temporal cortex (layer VI). The cingulate, retrosplenial, perirhinal, and lateral entorhinal cortices had lamina projecting to the visual cortex and separate lamina harboring zinc-containing cells. A spatial segregation of fluorescent and zinc-containing neurons was also seen in the claustrum. This integration or segregation of projecting and zinc-containing neurons may reflect the function of the cortical areas. N-methyl-D-aspartate receptor function is antagonized by physiological concentrations of zinc in vitro. It is proposed that zinc-positive projections from areas that perform basic visual functions are less likely to be modified by N-methyl-D-aspartate receptor-mediated processes than the zinc-negative connections from associational areas.
Garrett
B
B
Department of Neurobiology, University of Aarhus, Denmark.
Sørensen
J C
JC
Slomianka
L
L
D000818:Animals; D005260:Female; D007150:Immunohistochemistry; D008297:Male; D051379:Mice; D013572:Synaptic Vesicles / Q000737:chemistry*; D014793:Visual Cortex / Q000033:anatomy & histology / Q000737:chemistry*; D015032:Zinc / Q000032:analysis* / Q000378:metabolism
D015032:Zinc