Study Of Thymocyte Apoptosis And Related Mechanism And Expression Of INOS In Mice Induced By Morphine

Part I Effect of NOS Inhibitor L-NAME on Morphine-induced CPP and Withdrawal Symptoms of morphine dependent miceObjective To study the effect of NOS inhibitor NG-nitro-L-arginine methyl ester (L-NAME) on the conditioned place preference (CPP) and spontaneous withdrawal syndrome in morphine-dependent mice model and to explore the role of L-NAME in opioids psychological and physical dependence.Methods Forty female Balb/C mice were randomly assigned to saline control, morphine, morphine plus naloxone and morphine plus L-NAME groups. Mice in morphine group were injected by i.p. with morphine twice a day for 7 days in ascending schedule, while those in morphine plus naloxone and morphine plus L-NAME groups were injected by i.p. with naloxone (5mg/kg) or L-NAME (40mg/kg) 5 minutes before the injection of morphine. And mice in control group were treated by saline according to control principle. CPP (non-preferred compartment in white chamber) was recorded before treatment and 6 hours after the last injection. Withdrawal signs including jumping, incubation period of jumping, weight loss, rearing, stretching and diarrhea were recorded before treatment and 6 hours after the last injection for 30 minutes. Data were analyzed using one-way ANOVA, followed by LSD.Results 1. There were no difference in CPP before the treatment among the 4 groups ( P>0.05). The time of staying in the white chamber in morphine group was significantly longer than control after the last injection (P<0.01), while no significant difference were observed among that in morphine plus naloxone and morphine plus L-NAME groups(P>0.05). Time was significantly shorter in morphine plus naloxone and morphine plus L-NAME groups than morphine group(P<0.05). 2. Among the withdrawal signs, scores of jumping, weight loss, rearing, stretching were significantly higher in morphine group than control, while...