UCLA

Zebrafish (Danio rerio) hold immense promise for the study of learning and memory. Several attractive properties characterize this vertebrate animal model. For instance, zebrafish possesses a relatively reduced neural circuitry, which facilitates the drawing of causal relationships between changes on the behavioral scale to changes on the cellular-molecular level. They can also be affected by and absorb pharmacological agents in bath, and undergo learning and memory paradigms as early as 5 days post-fertilization (dpf). In particular, following a brief introduction of a noxious stimulus, allyl isothiocyanate (mustard oil, MO), 5-6 dpf zebrafish exhibit short-term sensitization. This memory has been demonstrated behaviorally through increased thigmotaxis and locomotion. However, the neuromodulatory mechanisms behind this non-declarative, non-associative form of memory remains to be elucidated. Exploiting this animal model’s strengths, we placed zebrafish under high-throughput pharmacological dissections with dopamine-receptor antagonists SCH-23390, eticlopride hydrochloride, haloperidol, and L-745,870 trihydrochloride in order to determine the role of dopamine and delineate receptor subtype-specific influences. These blockades have not only confirmed the role of dopamine, but also have demonstrated a differential involvement of the receptor subtypes within the two behaviors. Nonetheless, further investigations are required in order to determine the influence of other neuromodulators in the establishment of MO-induced short-term sensitization.