title: Changes in microRNA expression profile in hippocampus during the acquisition and extinction of cocaine-induced conditioned place preference in rats.
abstract: BACKGROUND
  MicroRNA (miRNA) emerges as important player in drug abuse. Yet, their expression profile in neurological disorder of cocaine abuse has not been well characterized. Here, we explored the changes of miRNA expression in rat hippocampus following repeated cocaine exposure and subsequent abstinence from cocaine treatment.
  
  
  RESULTS
  Conditioned place preference (CPP) procedure was used to assess the acquisition and extinction of cocaine-seeking behavior in rats. MiRNA microarray was performed to examine miRNAs levels in rat hippocampus. Quantitative RT-PCR was conducted to further confirm results in microarray study. Finally, bioinformatic predictions were made to suggest potential target genes of cocaine-responsive miRNA in this study. MiRNA array found that 34 miRNA levels were changed in rat hippocampus while acquiring cocaine CPP and 42 miRNAs levels were altered after the cocaine-induced CPP were extinguished, as compared to normal controls. The findings from qRT-PCR study support results from microarray analysis.
  
  
  CONCLUSIONS
  The current study demonstrated dynamic changes in miRNA expression in rat hippocampus during the acquisition and extinction of cocaine-induced CPP. Some miRNAs which have been previously reported to be involved in brain disorders and drug abuse, including miR-133b, miR-134, miR-181c, miR-191, miR-22, miR-26b, miR-382, miR-409-3p and miR-504, were found to be changed in their expression following repeated cocaine exposure and subsequent abstinence from cocaine treatment. These findings may extend our understanding of the regulatory network underlying cocaine abuse and may provide new targets for the future treatment of drug abuse.
authors.forename: Chun-Lin
authors.initials: CL
authors.lastname: Chen
authors.forename: Hailin
authors.initials: H
authors.lastname: Liu
authors.affiliation: Department of Human Anatomy, Nanjing Medical University, 140 Hanzhong Road, Nanjing 210029, China. guanxw918@njmu.edu.cn.
authors.forename: Xiaowei
authors.initials: X
authors.lastname: Guan
mesh_terms: D000818:Animals; D003042:Cocaine / Q000494:pharmacology; D003214:Conditioning, Classical / Q000187:drug effects*; D005108:Extinction, Psychological; D005786:Gene Expression Regulation / Q000187:drug effects*; D006624:Hippocampus / Q000378:metabolism*; D008297:Male; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D051381:Rats; D017208:Rats, Wistar
chemical_list: D035683:MicroRNAs; D003042:Cocaine