Effects of OA (A) and DA (B) receptor antagonists on olfactory memory retrieval. Twelve groups of crickets were each subjected to 2-trial appetitive (left) or 6-trial aversive (right) olfactory conditioning trials. On the next day, each group was injected with 3 μl of saline or saline containing 1 μM epinastine, 1 μM mianserin, 500 μM fluphenazine, 500 μM chlorpromazine or 500 μM spiperone at 30 min before the final test. Preference indexes for the rewarded odor (in the case of appetitive conditioning) or unpunished control odor (in the case of aversive conditioning) before (white bars) and one day after (black bars) conditioning are shown with means + SEM. The results of statistical comparison before and after conditioning (Wilcoxon’s test) and between experimental and saline-injected control groups (Mann-Whitney test) are shown as asterisks (*P < 0.05; **P < 0.01; ***P < 0.001, NS P < 0.05). Modified from Mizunami et al. .