Effects of Clenbuterol and Cyclosporin A on the Myosin Heavy Chain mRNA Level and the Muscle Mass in Rat Masseter

The Journal of Physiological Sciences

Yasutake Saeki²  Ayao Hirashita¹  Chihiro Arai¹  Yoshiki Ohnuki²  Daisuke Umeki¹ 

[1] Department of Orthodontics, Tsurumi University School of Dental Medicine;2Department of Physiology, Tsurumi University School of Dental Medicine

关键词: myosin heavy chain mRNA;    muscle mass;    clenbuterol;    cyclosporin A;    real time RT-PCR;   

DOI  :  10.2170/physiolsci.RP002206

学科分类：生理学

来源: Springer

【 摘 要 】

References(39)Cited-By(3)To gain more insight into the molecular mechanism of muscle growth and fiber-type transformations, we analyzed the effects of β2-adrenergic agonist clenbuterol (CB) and/or cyclosporin A (CsA), a potent inhibitor of calcineurin (CaN), on the muscle mass as well as on the mRNA levels of myosin heavy chains (MHC I, IIa, IId/x, IIb), using a real-time RT-PCR with specific primers in rat masseter. In comparison with control, the CB treatment significantly decreased the MHC I mRNA level (p < 0.01), but increased the MHC IId/x mRNA level (p < 0.01), and the CsA treatment significantly decreased the MHC I mRNA level (p < 0.05) in association with the significant decrease in MHC IIb mRNA level (p < 0.05). The CB+CsA treatment significantly decreased the levels of MHC I (p < 0.01) and IIa mRNAs (p < 0.05), but increased the MHC IId/x mRNA level (p < 0.001) in association with a significant decrease in MHC IIb mRNA level (p < 0.01), in comparison with control. The masseter muscle mass was significantly (p < 0.001) increased by either the CB or the CB + CsA treatment, but decreased with the CsA treatment (p < 0.01). These results suggest that in rat masseter muscle, CB has an anabolic action accompanying MHC mRNA I IIa IId/x sequence transition independently of CaN-signaling pathways, and CaN is involved in the type I fiber gene expression and the muscle mass maintenance of type IIb fiber.

【 授权许可】

Unknown