Effect Of Citalopram On Heroin-induced Conditioned Place Preference Of Rats

ObjectiveThe present study aim to observe the effect of selective serotonin reuptake inhibitor Citalopram on heroin-induced conditioned place preference (CPP) of rats. On this basis, we try to determine the function of serotonin in the addiction of heroin.Materials and Methods1 CPP experimental systemThe video trace CPP experimental system of rats was composed of shuttle box, sound-proof container, video system and computer.Mice Track software was applied in the analysis of the video stream.2 Animals36 Male Sprague-Dawley rats were randomly divided into three groups, namely low-dose treatment group, high-dose treatment group, and controls, 12 rats in each group.3 Methodsa) The establishment of heroin-induced CPP of rats(1) Conditioning session: blocking boards were used to partition the gray and black area of the shuttle box. Rats administered with heroin would be put in the gray area. Three groups of rats were all injected with heroin (0.5mg/3ml/kg) every morning and then placed in the gray area for 30 minutes, afterward rats were injected i.p. with normal saline (3ml/kg) in the afternoon and placed in the black area for 30 minutes. The above process was run once a day, 6 days continuously.(2) Testing session: 24 hours after the 6th day of conditioning session (Day 8), the blocking board was substituted by passage board. Then, rats were placed into the shuttle box for 20 minutes, video images were recorded, and the time of rats reside in the black and gray area was estimated, respectively. In the following 28 days, citalopram was given to the rats everyday. On Day 37, video image was captured again. At the end, on Day 52, 14 days after the last administration of citalopram to the rats, video image was recorded.4 Administration of CitalopramFrom Day 9 to Day 36, three groups of rats including low-dose treatment group, high-dose treatment group, and controls were injected with citalopram (5mg/3ml/kg or 15mg/3ml/kg), or vehicle (NS 3ml/kg) everyday.5 Statistical analysisThe time of the rats reside in the gray area were obtained. Data between groups were analyzed using one-way analysis of variance (ANOVA).Result1 The potency of the experimental systemRats were allowed to move freely in the shuttle box, which has pretty low degree of environment disturbances. By using the video tracking system, we couldobserve and record the activities of the rats through the monitor, and the video data obtained was direct and objective.Mice Track is a user-friendly software which providing fine and continuous video data.2 Effect of Citalopram on heroin-induced CPP of rats24 hours after the conditioning session (Day 8), the time of rats reside in the gray area among three groups of rats was not showing significant difference. After the administration of Citalopram for 28 days continuously, significant difference was found in the time of rats reside in the gray area among three groups of rats. On Day 52, 14 days after the last administration of citalopram to the rats, the time of rats reside in the gray area among three groups of rats showed no difference.ConclusionCitalopram has inhibitive effect on heroin-induced conditioned place preference of rats.