Impulsive-like behaviors of rats in Y-maze task induced by pramipexole and its mechanism / 中国药理学与毒理学杂志

ABSTRACT

OBJECTIVE To analyze impulsive-like behaviors of SD rats induced by pramipexole in Y-maze avoidance tasks. METHODS Behaviors of SD rats in Y-maze avoidance tasks were recorded with a camera and analyzed by Noldus Etho Vision XT8 software after acute subcutaneous injection of pramipexole(0.1,1 and 10 mg · kg-1),including right reaction numbers of 20 consecutive avoidance tasks,shuttle number of times between the three arms of Y-maze, distance covered in Y-maze and time spent in safe arms during 20 consecutive avoidance tasks. Then,the prepulse inhibition(PPI)of the startle reflex test was used to assess the effect of pramipexole on sensorimotor gating (SG). Effects of pramipexole on the dialyzed content of monoamine neurotransmitter and its metabolites in the striatum and amygdala of SD rats were measured by microdialysis in vivo. RESULTS Compared with normal control group,the rats of pramipexole group showed a significant increase in the shuttle number of times and distance covered in Y-maze between Y-maze avoidance tasks(P<0.01),but a statistically significant decrease in the time spent in safe arms(P<0.01),while the number of right reactions in Y-maze avoidance tasks was not changed. Such premature responses were quite similar to certain impulsive-compulsive behaviors in rodent models,such as five-choice serial reaction time tasks. In the PPI test,pramipexole displayed an impairing effect on SG(P<0.01). The microdialysis results showed that there was an increase of dopamine and 5-hydroxytryptamine in the striatum of pramipexole group, but not statistically significant. Monoamine neurotransmitters and their metabolites were not significantly changed in the amygdala. CONCLUSION Pramipexole can induce impulsive-compulsive behaviors in Y-maze avoidance tasks,which might be attributed to impaired SG.