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Cardiac electrophysiological effect of (S)-OTS·HCl, a derivative of Baogongteng A

WANG Hong-wei1, ZHANG Ying2, LI Ci-zhen3, LIU Yuan-mou3, YANG Zhi-fang1   

  1. 1. Department of Physiology, Shanghai University of Medicine and Health Science, Shanghai 201318, China; 2. Experimental Center, Basic Medicine Faculty of Shanghai Jiao Tong University, Shanghai 200025, China; 3. Department of Physiology, Basic Medicine Faculty of Shanghai Jiao Tong University,Shanghai 200025, China
  • Online:2017-02-28 Published:2017-02-28
  • Supported by:

    Key Project of Science and Technology Commission of Shanghai Municipality, 06JC14045; Scientific Research Innovation Project of Shanghai Education
    Committee, 13yz150; Subject of Health School Affiliated to Shanghai University of Medicine and Health Sciences, FA1-3903-16-117067

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Abstract:

Objective · To study the electrophysiological effect of (S)-OTS·HCl on the heart. Methods · The conventional intracellular recording, electrocardiograph (ECG) and Langendorff cardiac perfusion technique were employed to investigate the effect of (S)-OTS·HCl on in-vivo and in-vitro hearts of guinea pigs and rabbits. Results · (S)-OTS·HCl could bind to M2 muscarinic receptors and dose-dependently prolong the RR intervals significantly in vivo. It had no effect on resting potential (RP), action potential amplitude (APA), and maximum upstroke velocity of phase 0 (Vmax) of ventricular myocytes. Instead, 1×10-5 mol/L (S)-OTS·HCl could shorten the action potential duration at 50 percent repolarization (APD50) and APD90 to 91.6% and 90.9%, respectively. And the spontaneous depolarization rate of phase 4 (SDR) of sinus nodes was reduced to its 13.7% when rabbit sinus nodes were exposed to 1×10-7 mol/L (S)-OTS·HCl. (S)-OTS·HCl could inhibit Ca2+channel effectively. It decreased APA and Vmax of sinus nodes and attenuated the cardiac contractility in vitro. Conclusion · (S)-OTS·HCl is a potent cholinergic agonist and has negative chronotropic, dromotropic, and inotropic effects on hearts via binding to M2 muscarinic receptors.

Key words: (S)-OTS·HCl, cholinergic agonist, action potential, electrocardiograph