the TaqMan High Capacity cDNA Reverse Transcription kit (Applied Biosystems, Foster City, CA). Thereafter, they were processed with the TaqMan Universal PCR kit with the mouse or rat CHRNA5 gene expression assay (Applied Biosystems); controls consisted of either β-actin or 18S. Samples were quantified by real-time RT-PCR (7900 Real-Time PCR system; Applied Biosystems). All data were normalized in accordance with the mean housekeeping mRNA expressing levels as an internal control. Comparison between groups made using the method of 2−ΔΔCt.
