title: GluR2/3 label expression of the AMPA-type glutamate receptor in the hippocampal formation of the homing pigeon stabilizes just after birth.
abstract: The compositions of the glutamate AMPA-type receptors influence the neural response and the subunits GluR2/3 has been referred to as essential for receptor trafficking and synapse consolidation. We investigate the GluR2/3 occurrence and expression in the hippocampal formation of newly born homing pigeons by a semi-quantitative approach, the Western-blotting technique and by immunohistochemistry. Immunoreactivity for GluR2/3 occurs before hatching has been evident in neuropil that was fully dispersed over the hippocampus proper (HP) and the area parahippocampalis (APH). Although many HP cells are NeuN-positives, a specific neuronal protein indicating that they are already differentiated as neurons while not one contains GluR2/3 at the hatching day (P0). Few neurons at the APH seem to express GluR2/3 at P0, but 3 days later (P3) the GluR2/3 labeling can be recognized in many HP neurons, showing a distribution pattern that resembles the adult, gradually increasing in intensity until P10. Also, the Western-blot shows an augment between P0 and P3, remaining stable after that. The enhancement of the neuronal label at P3 coincides with the retraction of the GluR2/3 label in neuropil, reducing their occurrence during the maturational period to become restricted to the dorsomedial portion as reported for adults. As the HP GluR2/3-containing cells are supposedly projecting neurons, taking together, the results signalize the relevance of the GluR2/3 in post-hatch formation of avian hippocampal circuitry in which the third day seems to be the critical period.
authors.affiliation: Núcleo de Pesquisa em Neurociências, Universidade Cidade de São Paulo, 03071-000 São Paulo, SP, Brazil.
authors.forename: Ana Lucia Beirão
authors.initials: AL
authors.lastname: Cabral
authors.forename: Renato Figueiredo
authors.initials: RF
authors.lastname: Santana
authors.forename: Vinicius Otavio
authors.initials: VO
authors.lastname: da Silva
authors.forename: Cláudio Antonio Barbosa
authors.initials: CA
authors.lastname: de Toledo
mesh_terms: D000367:Age Factors; D000818:Animals; D015153:Blotting, Western; D010856:Columbidae / Q000378:metabolism*; D006624:Hippocampus / Q000378:metabolism*; D007150:Immunohistochemistry; D009474:Neurons / Q000378:metabolism; D021122:Protein Subunits / Q000378:metabolism*; D018091:Receptors, AMPA / Q000378:metabolism*
chemical_list: D021122:Protein Subunits; D018091:Receptors, AMPA