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67 Functional ammo acid receptors in embryonic neocortex
Author(s) -
Boyce L.H.,
Owens D.F.,
Kriegstein A.R.
Publication year - 1996
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 - 10.1016/0736-5748(96)80262-0
Subject(s) - citation , neocortex , embryonic stem cell , library science , neuroscience , biology , computer science , genetics , gene
In cortical glia cells kainatc-induced Ca*’ fluxes are mostly due to the activation of AMPA receptors. Hence they are enhanced by cyclothiazide but not by concanavalin A and are blocked by GYKI53655. By using fura 2-based video imaging and simultaneous recording of Ca” entry and Nd currents under voltage-clamp conditions, we studied some of the properties of these receptors in CG-4 cells and O-2A progenitors from primary cultures of rat cortex. In undifferentiated CG-4 and O-2A progenitor cells both Ca2+ fluxes and Na’ currents were blocked by Joro spider toxin (JSTx). However, neither JSTx nor Argiotoxin 636 effectively blocked either parameters in cells differentiated into type II astrocytes, although they still flux appreciable amounts of Ca”. When cells were differentiated in oligodendrocytes they showed an intermediate sensitivity to block by JSTx. Western blot analysis of the expression of AMPA-receptor subunits showed a marked increase in the concentration of GluRB in CG-4 cells as they differentiated in type II astrocytes, and a moderate increase of the same subunit in the oligodendrocytes. These results show that AMPA receptors in cells of the O-2A lineage may contain variable amounts of edited GIuRB subunit and that the subunit composition of the receptor is developmentally regulated. Current experiments on the properties of recombinat AMPA receptors expressed in HEK 293 cells also suggest these possibilities.