Figure 9.

Prenatal cocaine exposure decreased the sensitivity of the locomotor activity to cocaine and apomorphine in postnatal rats. A, Normalized horizontal distances traveled by the rat were measured during ten 10 min sessions at P22. The horizontal distance traveled of each session was normalized to that of the first session. Cocaine (Coc) challenge was given after the first session. (n = 6–16) B, Average horizontal distances traveled by the P24 rat were measured during four 10 min sessions. Apomorphine (Apo) challenge was given after the first session. (n = 11–13). Significant difference between Sal and Coc of the same session is marked by an asterisk: *p < 0.05, t test. Error bars indicate SEM.