In the present study, when combined with cocaine, CTEP potentiated the hyperlocomotion on spinophilin-KO mice without affecting behavioral sensitization or conditioned place preference, key paradigms to study cocaine addiction in animal models, suggesting that the CTEP effect on KO mice at the dose used may be related mostly to motor aspects, in accordance with previous reports that blockage of mGluR5 produces hyperlocomotion [43, 17]. This evidence concerns the gene GRM5 and cocaine dependence.