Ethanol induces subtype-specific up-regulation of muscarinic acetylcholine receptor mRNA in neurohybrid cell lines.
Effects of sub-chronic ethanol treatment on the mRNA levels of muscarinc acetylcholine receptor (mAChR) subtypes were studied in two neurohybrid cell lines, NG108-15 and NCB-20. The former expresses only m4-mAChRs, while the latter expresses m1- and m4-mAChRs. Exposure to 200 mM ethanol for 1 to 3 days induced a time-dependent increase in the levels of m4-mAChR mRNA in NG108-15 and NCB-20 cells. In contrast, the levels of ml-mAChR mRNA and mAChR-mediated phosphoinositide hydrolysis in NCB-20 cells were unchanged. The ethanol-induced up-regulation of m4-mAChR mRNA was associated with a parallel increase in the levels of mAChR binding sites assessed by using [3H]quinuclidinyl benzilate. The mRNA up-regulation was closely correlated with a decrease in intracellular cyclic AMP concentration and the ethanol up-regulation was blocked by 8-bromo-cyclic AMP and forskolin, suggesting that m4-mAChR mRNA is under negative regulation by cyclic AMP. Thus, neurally-related cell lines are useful models for studying molecular mechanisms underlying ethanol-induced alteration of mAChR expression and function in the nervous system.
Fukamauchi
F
F
Department of Molecular Medical Science, Medical Research Institute, Tokyo Medical and Dental University, Japan.
Wang
Y J
YJ
Chuang
D M
DM
D000818:Animals; D005576:Colforsin / Q000494:pharmacology; D006224:Cricetinae; D000242:Cyclic AMP / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D000431:Ethanol / Q000494:pharmacology*; D006822:Hybrid Cells; D051379:Mice; D009474:Neurons / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D011976:Receptors, Muscarinic / Q000235:genetics*; D013997:Time Factors; D015854:Up-Regulation / Q000187:drug effects*
D012333:RNA, Messenger; D011976:Receptors, Muscarinic; D005576:Colforsin; D000431:Ethanol; D000242:Cyclic AMP