Acetylcholinesterase (AChE) mRNA in fast ret skeletal muscle is downregulated by both, electromechanical activity and denervation. One candidate mechanism that could explain decreased level of AChE mRNA in the denervated muscle is increased rate of its degradation. In order to test this possibility, total deproteined RNA was isolated from rat . SM and exposed to subcellular musculafractions prepared from contralateral m SM. After selected time intervals, we determined remaining AChE mRNA by nonradioactive Northern blot analysis. AChE mRNA remained at the same level during first 5 hours after denervation and abruptly fell after subsequent 13h. Further decrease in the transcript level proceed at much slower rate. Longer transcript (3.5kb) was more affected than the shorte (2.3kb) one. The level of alpha-actin mRNA was also decreased in the denervated muscle, and the rate of its disappearance wassimilar to that of AChE mRNA, suggesting that AChE mRNA is not specifically affected under such conditions. Degradations of AChE mRNA was observed in all subcellular fractions studied. Postmitochondrial and postpolysomal fractions exibited higher rate than polysomal fraction. We find experimental approach demonstraded here suitable for studies of degradation capacities of the specific mRNAs in the adult skeletal muscle. Our preliminary results suggests, that fall of AChE mRNA after denervation at least partly results from increased degradation of transcripts under such conditions.