Differential effects of aging on the distribution of calcium-binding proteins in a pretectal nucleus of the chicken brain.
The nucleus pretectalis (PT) of birds is an ovoid-shaped visuomotor cell group of the pretectum that receives tectal input and projects back to the optic tectum. We performed immunohistochemical single- and double-labeling to determine the distribution and abundance of neurons containing three calcium-binding proteins, parvalbumin (PV), calretinin (CR), and calbindin (CB), in the PT in chickens at three ages. We found that PV-positive and CR-positive cells co-localize and are largely found in the outer part of PT at all ages. The GluR4 subunit of the AMPA-type glutamate receptor was selectively localized to these neurons. CB-positive neurons, however, were largely absent from the PT in young and adult chickens. The abundance of PV-positive and CR-positive neurons in PT in old birds was indistinguishable from that in the younger birds, but CB-positive perikarya were 10-20-fold more common than in young birds, and were again mainly found in the outer part of PT. The overall abundance of neurons in PT was reduced to about 50% of its former abundance in the old birds, with this loss restricted to the central part of the nucleus. These data indicate that a cell loss process develops in PT as birds age, that parvalbuminergic and calretinergic neurons resist this process, and that this process is associated with increased expression of CB.
Santana
Renato F
RF
Laboratory of Neurosciences, City University of São Paulo, Rua Cesário Galeno 448, 03071-000 São Paulo, SP, Brazil.
Reiner
Anton
A
Britto
Luiz R G
LR
Toledo
Cláudio A B
CA
D000375:Aging / Q000378:metabolism*; D000818:Animals; D064032:Calbindin 2; D064026:Calbindins; D002645:Chickens; D009474:Neurons / Q000378:metabolism; D010320:Parvalbumins / Q000378:metabolism*; D018091:Receptors, AMPA / Q000378:metabolism; D064030:S100 Calcium Binding Protein G / Q000378:metabolism*; D013477:Superior Colliculi / Q000166:cytology / Q000378:metabolism*; D014795:Visual Pathways / Q000166:cytology / Q000378:metabolism*
D064032:Calbindin 2; D064026:Calbindins; D010320:Parvalbumins; D018091:Receptors, AMPA; D064030:S100 Calcium Binding Protein G; C104724:glutamate receptor ionotropic, AMPA 4