Abstract
Neuroadaptive changes that occur in the development of ethanol tolerance may be the result of alterations in gene expression. We have shown that PKCgamma wild-type mice develop tolerance to the sedative-hypnotic effects of ethanol after chronic ethanol treatment; whereas, mutant mice do not, making these genotypes a suitable model for identifying changes in gene expression related to tolerance development. Using a two-stage process, several genes were initially identified using microarray analyses of cerebellar tissue from ethanol-treated PKCgamma mutant and wild-type mice. Subsequent confirmation of a subset of these genes using quantitative real time reverse transcriptase polymerase chain reactions (qRT-PCR) was done to verify gene expression changes. A total of 109 genes from different functional classifications were identified in these groups on the microarrays. Eight genes were selected for verification as follows: three, Twik-1, Plp, and Adk2, were chosen as genes related to tolerance; another three, Hsp70.2, Bdnf, and Th, were chosen as genes related to resistance to tolerance; and two genes, JunB and Nur77, were selected as candidate genes sensitive to chronic ethanol. The results from the verification experiments indicated that Twik-1, which codes for a potassium channel, was associated with tolerance and appeared to be dependent on the presence of PKCgamma. No genes were confirmed to be related to resistance to tolerance; however, expression of two of these, Hsp70.2 and Th, were found to be sensitive to chronic ethanol and were added to the transcription factors, JunB and Nur77, confirmed by qRT-PCR, as a subset of genes that respond to chronic ethanol.