Figure 7.

Exogenous expression of P2Y₁ receptor increases the outgrowth index of Cx43-null neural progenitors. A, Phase contrast (top) and fluorescence (bottom) images obtained 30 hr after plating Cx43-null neurospheres transfected with eGFP-P2Y₁R. The arrowhead points to the core of the neurosphere. Scale bar, 24 μm. B, Calcium transient induced by 30 μm 2-MeS-ATP was mostly blocked by the P2Y₁R antagonist MRS-2179 (5 μm; n = 120 cells from 3 independent experiments), indicating proper function of the transfected receptor. C, Note the low frequency of spontaneous calcium oscillations recorded from Cx43-null progenitors and the increased frequency of these events in Cx43-null cells transfected with eGFP-P2Y₁R (the oscillations of each cell are represented by black and gray traces) (D). E, Thirty hours after adhesion to fibronectin-polylysine-coated substrate, the outgrowth index values of Cx43-null progenitors transfected with eGFP-P2Y₁R were similar to those of WT cells. Note that transfection of Cx43-null neurospheres with eGFP constructs did not increase the outgrowth index of Cx43-null cells, which was lower than that of WT controls. (^**p < 0.001; ANOVA; n = 30 neurospheres).