Effect of Shenmai Injection on L-type calcium current of diaphragmatic muscle in rats

Abstract

In this study, whole cell patch clamp recording technique was employed to investigate the effect of Shenmai Injection (SMI) on L-type calcium current of diaphragmatic muscle in rats. The result showed that when the diaphragmatic muscle cell was held at −80 mV and depolarized to +60 mV, 10 μl/ml, 50 μl/ml and 100 μl/ml SMI enhanced the inner peak L-type calcium current from −(6.8±0.7) pA/pF (n=7) to −(7.3±0.8) pA/pF (P>0.05,n=7), −(8.6±1.0) pA/pF (P<0.05,n=7) and −(9.4±1.2) pA/pF (P<0.05,n=7), respectively. The rates of L-type calcium current were increased by (7.34±2.37) %, (25.72±5.94) %, and (38.16±7.33)%, respectively. However, it had no significant effect on maximal activation potential and reversal potential. Our results suggested that SMI could activate the calcium channel of the diaphragmatic fibers of the rats, increase the influx of Ca²⁺, and enhance the contractility of diaphragmatic muscles.

Keywords

SMI / calcium-channel / diaphragm / patch-clamp techniques

References

[1] VassilakopouloT, Zakynthinos, RoussosC H. Respiratory muscles and weaning failure. Eur Respir J, 1996, 9(11): 2383-2383

[2] TaoQ G, ZhaoJ P, NiuR J. The experimental and clinical studies on the mechanism and treatment of diaphragm fatigu (Chinese). J Intern Int Med, 1996, 2(2): 62-62

[3] ZhaoJ P, NiuR J. The effect of SMI on the muscle stripe of diaphgram in rats with chronic hypoxia (Chinese). Chin J Tuber Respir Dis, 1995, 18(1): 53-53

[4] KolbeckR C, SpeirW A. Theophylline, fatigue, and diaphragm contractility: cellular levels of 45Ca and cAMP. J Appl Physiol, 1999, 70(5): 1933-1933

[5] PattersonM, ConstantinB, CognardC, et al. . Properties of calcium currents and contraction in cultured rat diaphragmatic muscle. Pflugers Arch-Eur J Physiol, 1999, 430837-837

[6] Marie-DominiqueF, TakeshiS, RolandB. cAMP-depedent moudulation of L-type calcium currents in mouse diaphragmatic cells. Respir Physiol, 1996, 1041-1

[7] NiuR J, FuJ, LiuH G. Effect of SMI and aminophylline on the apoptosis of muscle cells of small airways and gene expression of related genes (Chinese). Chin J Integ Trad West Med, 2002, 22(1): 40-40

[8] YinL H, WoX D. Advances in the pharmacological and clinical studies of SMI (Chinese). J Zhejiang Col Trad Chin Med, 2001, 25(6): 65-65

[9] ZhaoJ P, NiuR J. Experiment study on the effect of Sheng-Mai Injection on the contractivity of diaphragm and its mechanism. Chin Med J, 1995, 108(2): 90-90