Figure 2From: The gamma-aminobutyric acid type B (GABAB) receptor agonist baclofen inhibits morphine sensitization by decreasing the dopamine level in rat nucleus accumbensThe induction of behavioral sensitization of morphine in rat. Two groups of rats were exposed to morphine or saline for 4 consecutive days. Rats were given morphine or saline once daily on day 1 and twice daily on days 2–4 as described previously. The locomotor activity was monitored for 3 h in the chambers after the first injection once daily. Each point represents the total distance traveled for the 3 h test period. Data are shown as means ± S.E.M (n = 8 per group). * P < 0.01 compared to the first administration within group; # P < 0.05 and ## P < 0.01 compared to the corresponding saline control group.Back to article page