Morphine incubation craving-NAc_small RNA sequencing

The current study aimed at addressing two questions: 1) How the expression of key miRNAs is altered in the NAc during the cue-induced incubation of morphine craving? 2) Which is/are the target gene(s) and what is/are the regulatory mechanism(s) of gene(s) in response to the candidate miRNAs? To answer these two questions, the cue-induced incubation of the morphine craving model was first established by using the conditioned place preference (CPP) paradigm. Then, the aberrant expression of miRNAs was identified in the NAc tissue by RNA-sequencing. Overall design: The NAc tissues from C57BL/6N mice from the two groups that were subjected to morphine induced CPP model test 1 (T1) and test 2 (T2) were harvested; three samples (6 mice) from each group were used for total RNA isolation. RNA-seq was performed by Novogene Co., LTD (Beijing, China). In short, following RNA quantification and qualification, RNA integrity was examined with the RNA Nano 6000 assay kit and Agilent Bioanalyzer 2100 library preparation for small RNA sequencing system (Agilent Technologies, CA, USA). Any library preparations in this study were sequenced on an Illumina HiSeq 2500 platform (Illumina, San Diego, CA, USA). We explored the occurrence of miRNA families identified from the samples in other species and used miFam.dat (http://www.mirbase.org/ftp.shtml) for known miRNAs to determine families. New miRNA precursors were submitted via the Rfam website (http://rfam.sanger.ac.uk/search/) for Rfam family identification.