Alcohol-induced Reward Memory is Positively Associated With Persistent High Levels of RACK1, LC3-II/I and Synaptophysin in Hippocampus of C57BL/6J Mice.

Li-Tao LIU; Jie-Jun ZHU; Li-Hong WAN; Li-Ming ZHOU

Objective: The present study was designed to investigate the pattern of reward memory to alcohol during acquisition, CPP-maintenance, and reacquisition in mice and levels of RACK1, LC3-II/I and synaptophysin (SYP) in hippocampus to reveal the long-term alterations in brain reward systems. Methods: Male C57BL/6J mice were administered with ethanol (20% v/v) intraperitoneally at a dose of 2 g/kg to establish the reward model. During acquisition, CPP-maintenance, and reacquisition phase, CPP scores were measured and protein levels of RACK1, LC3-II/I and SYP in hippocampus were determined by western blotting. Results: Alcohol induced reward memory persistent enhanced during acquisition, CPPmaintenance, and reacquisition phase, which was reflected by enhanced CPP scores to alcohol. RACK1 is known a regulator of the rewarding processes and we found that the endogenous RACK1 protein was significantly up-regulated in parallel with increase of CPP in acquisition and CPP-maintenance phase in the hippocampus. Conversely, it declined notably in reacquisition phase. The same phenomenon occurred in LC3-II/I level. However, SYP, the presynaptic membrane marker, maintained the high level in the whole phases. Using Pearson correlations analysis, we found that the alcohol preference was significantly associated with RACK1, LC3-II/I and SYP expression in hippocampus. Conclusions: High expression of RACK1 at the hippocampus seemed to be related to alcohol addiction memory and not just to its ability to establish conditioned preference.

SYNAPTOPHYSIN; ETHANOL; HIPPOCAMPUS (Brain); WESTERN immunoblotting; PEARSON correlation (Statistics)

Journal of Neurological Sciences, 2015, Vol 32, Issue 4, p718

1300-1817

Academic Journal