Fig. 1.

Effects of a D2 antagonist, spiperone, on choroidal thickness over the day. A Intravitreal atropine alone (red) caused prominent choroidal thickening for a few hours which was reduced by co-application of spiperone (orange). If atropine was applied to one eye, also the saline- (dark green) or ascorbic acid– (light green) injected fellow eye developed a thicker choroid, although with faster recovery to baseline (n = 7 chickens, one eye injected with atropine, the other with saline; n = 12 chickens, one eye combined atropine + spiperone injection, the other with vehicle). All eyes recovered to baseline during the following night. B Untreated eyes (blue, n = 8 untreated chickens) or eyes injected with ascorbic acid (light green) showed no choroidal thickness changes over the day. However, spiperone caused long-lasting choroidal thinning (yellow) (n = 12 chickens, one eye injected with spiperone, the other with ascorbic acid). The blue and yellow bars in the bottom denote diurnal dark and light cycles. Colors of brackets denote which data were compared, as denoted by asterisks of the same color. Two-way repeated measures ANOVA with Tukey–Kramer post hoc test; * p < 0.05, ** p < 0.01