Treatment with INF-γ plus TNF-α causes an increase in Cx43
immunoreactivity at contacts between rat microglia in culture and an
increase abundance of Cx43. Cellular distribution of Cx43 was
determined by immunofluorescence. (A) Distribution of
Cx43 mmunofluorescence in a control culture at time 0. Most of the
labeling was diffuse and localized to the perinuclear region.
(B) In a culture treated with 1 ng/ml INF-γ
plus 1 ng TNF-α for 9 h, there was marked labeling at
intercellular appositions and reduced labeling in perinuclear regions.
(Bar, 50 μm.) (C) The relative levels of Cx43 were
determined by Western blot analysis of total homogenates of microglia
(150 μg of protein per lane). Lane H is from a sample of rat heart to
identify the mobility of different phosphorylation states of Cx43. NP
is an unphosphorylated form, and P2 and P3 are two phosphorylated
forms. The other lanes correspond to cultures of microglia treated with
1 ng/ml INF-γ plus 1 ng/ml TNF-α for 0, 2, 4, and
9 h.