Figure 2.

The effect of intravitreal (IVIT) dopamine (DA), serotonin, melatonin, and saline (vehicle) on vertical movement during the (A) light phase and (B) dark phase of the light/dark cycle. Difference scores were obtained by subtracting the drug injection performance from the non-injected control performance. Rats were tested 30 min after IVIT injection in all groups with the exception of an additional group receiving 2 µl of control solution bilaterally and a second group receiving 50 µg of DA 3 h before testing. Values in all control animals tested 0.5 h after injection were combined into a single control group as they did not differ significantly from each other. The T-bars represent the SEM.