Abstract:

Objective To explore the mechanism of ZMS regulation of M₂ muscarinic receptor mRNA expression. Methods In vitro cultured CHOm2 cells were divided into ZMS 1 group (treatment with 1×10^-5 mol/L ZMS for 24 h), ZMS 2 group (treatment with 1×10^-5 mol/L ZMS for 24 h and 1 μg/mL cycloheximide for 12 h) and ZMS 3 group (treatment with 1 μg/mL cycloheximide for 4 h and 1×10^-5 mol/L ZMS for 24 h), and their corresponding control groups were also established (substitution of ZMS by DMSO). Actinomycin D was added to cultured CHOm2 cells of each group to inhibit the synthesis of mRNA. CHOm2 cell samples were taken at different time points, the relative expression of M₂ receptor mRNA was detected by Real-time PCR, and half life of M2 receptor mRNA was calculated. Results Compared with corresponding control groups, the half life of M2 receptor mRNA of CHOm2 cells in ZMS 1 group and ZMS 2 group was significantly prolonged [(4.75h±0.54) h vs (2.13±0.23) h, P<0.05; (5.43±1.13) h vs (2.46±0.09) h, P<0.05].There was no significant difference in half life of M2 receptor mRNA of CHOm2 cells between ZMS 3 group and its corresponding control [(3.06±0.23) h vs (3.00±0.20) h, P>0.05]. Conclusion De novo protein synthesis is required for the enhancement of M2 receptor mRNA stability regulated by ZMS.

Key words: ZMS, CHOm2 cells, muscarinic M₂ receptor mRNA, Real-time PCR, protein synthesis inhibitor