Figure 2.

Cocaine partially inhibits dark-adaptation. Visual sensitivity was measured by observing the escape response of dark-adapted fish to varying levels of incident light. (a) The apparatus with a fish turning to avoid the moving black panel. (b) Cocaine induces a log-unit drop in visual sensitivity of dark-adapted wild-type fish, whereas lidocaine has no effect. Fish from the control family (Con) showed normal cocaine sensitivity. Fish from dum and jpy that showed normal cocaine-induced CPP (NR) also had normal sensitivity to the drug in the visual test. In contrast, fish from dum and jpy families that showed low cocaine-induced CPP (LR) were also insensitive to the visual effect of the drug. Also shown are “jumpy” fish from the jpy family (jpyJ) with undeterminable CPP but relative insensitivity to cocaine in the visual test. Fish from the gts family showing both normal and low cocaine-induced CPP (NR and LR) show normal sensitivity to the drug in the visual test (*, P < 0.05 when compared with wild-type fish treated with cocaine as measured by ANOVA, with a minimum of four fish from each group). Error bars represent ± SEM.