RO5256390 or RO-5256390 is a drug developed by Hoffmann-La Roche which acts as an agonist for the trace amine associated receptor 1 (TAAR1).

[3] In contrast with acute exposure however, chronic administration of RO5256390 for 14 days increased the excitability of VTA dopaminergic and DRN serotonergic neurons.

[1][2] In addition, it dose-dependently inhibited the hyperlocomotion induced by the NMDA receptor antagonists phencyclidine (PCP) and L-687,414.

[1][2] RO5256390 is said to produce a brain activity pattern similar to that of the antipsychotic olanzapine in rodents and hence is presumed to have antipsychotic-like properties.

[2] In contrast to classical antipsychotics however, RO5256390 did not produce extrapyramidal-like symptoms in rodents and instead could reduce the catalepsy induced by haloperidol.