Figure 4. Hypoxia-reoxygenation reduces dye coupling in rat astrocytes; an effect potentiated by high glucose.

(A–D) Fluorescence micrographs of LY coupling in astrocytes under control conditions (A), at 1 h of reoxygenation after 3 h hypoxia in 5 (B) or 27 mM glucose (C), and at 1 h of reoxygenation after 6 h hypoxia in 27 mM glucose (D). The (*) in panels A–D denotes the cell microinjected with LY. Bar = 60 μm. (E) Average number of astrocytes to which LY spread from an injected cell after different reoxygenation periods following 3 h of hypoxia in 5 (), 27 (●) or 0 mM (○) glucose (expressed as percentage of the number in control conditions, dashed line). Zero time is at the beginning of reoxygenation. ** p<0.005, *** p<0.001, (●) v/s (). (F) LY coupling by astrocytes after increasing reoxygenation periods following 6 h hypoxia in 5 (), 27 (●) or 0 mM (○) glucose. *** p<0.001, (●) vs (●); ††† p<0.001, †† p<0.005, (●) vs (○); ## p<0.005, # p<0.05; () vs (○). (C) LY coupling at 1 h reoxygenation after 3 (□) or 6 h (■) hypoxia in different glucose concentrations. * p<0.05; (■) vs (□). For each graph values are means ± S.E. of 10 cells in a representative experiment of five; separate cultures were used for each time point.