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GABA Aβ2–3 immunoreactive cells in the developing chick retina
Author(s) -
Barros Pedro Henrique Oliveira Cavalcanti,
Calaza Karin da Costa,
Gardino Patrı́cia Franca
Publication year - 2003
Publication title -
international journal of developmental neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.761
H-Index - 88
eISSN - 1873-474X
pISSN - 0736-5748
DOI - 10.1016/s0736-5748(02)00106-5
Subject(s) - neurogenesis , immunohistochemistry , biology , neurotransmitter , gabaa receptor , receptor , ontogeny , immunocytochemistry , inhibitory postsynaptic potential , retina , embryonic stem cell , microbiology and biotechnology , neuroscience , endocrinology , medicine , central nervous system , biochemistry , immunology , gene
Gama‐aminobutyric acid (GABA) is the major inhibitory neurotransmitter in the central nervous system (CNS). It has been shown that GABA is an important factor for CNS maturation and that its functions are mainly mediated by GABA A receptors. Thus, in order to fully comprehend the role of GABA during development, it is essential to establish the developmental features of the catalytic subunits (β) of GABA A receptor. Here, we determine the ontogenesis and neurogenesis of cells expressing β2–3 subunits of GABA A receptor (GABA Aβ2–3 ) in the chick retina. In the ontogenetic experiments, only the immunohistochemistry for GABA Aβ2–3 approach was employed. For neurogenesis a double‐labeling method (autoradiography and immunohistochemistry) was applied. [H 3 ]‐thymidine was injected into eggs (2–11 days) and the embryos were sacrificed at embryonic day 19 (E19). GABA Aβ2–3 immunohistochemistry was processed and then autoradiography was performed. We used a cumulative counting method to quantify the autoradiographic grains. The ontogenesis study revealed that at E9, GABA Aβ2–3 immunoreactivity was restricted to the inner plexiform layer and the first cell bodies immunoreactive to GABA Aβ2–3 were seen at E14. Thereafter, the number of cell bodies and the intensity of GABA Aβ2–3 immunoreactivity increased until the adult pattern was established. The neurogenesis study showed that cells that will express GABA Aβ2–3 were generated between E6 and E9. In addition, from E7 to E9 the rate of neurogenesis of GABA Aβ2–3 immunoreactive cells quickly increases. Therefore, the detection of GABA Aβ2–3 occurred only after the end of generation period of this cell population.