Identification of evodiamine and rutecarpine as novel TMEM16A inhibitors and their inhibitory effects on peristalsis in isolated Guinea-pig ileum.

The transmembrane member 16A (TMEM16A)-encoded Ca2+-activated Cl- channel (CaCC) is expressed in interstitial cells of Cajal (ICCs) and involved in the generation of the slow-wave currents of gastrointestinal (GI) smooth muscles. TMEM16A modulators have been shown to positively or negatively regulate the contraction of gastrointestinal smooth muscle. Therefore, targeting the pharmacological modulation of TMEM16A may represent a novel treatment approach for gastrointestinal dysfunctions such as constipation and diarrhoea. In this study, evodiamine and rutecarpine were extracted from the traditional Chinese medicine Evodia rutaecarpa and identified as novel TMEM16A inhibitors with comparable inhibitory effects. Their effects on intestinal peristalsis were examined. Whole-cell patch clamp results show that evodiamine and rutecarpine inhibited TMEM16A Cl- currents in CHO cells. The half-maximal inhibition values (IC50) of evodiamine and rutecarpine on TMEM16A Cl- currents were 11.8 ± 1.3 µΜ and 9.2 ± 0.4 µM, and the maximal effect values (Emax) were 95.8 ± 5.1% and 99.1 ± 1.6%, respectively. The Lys384, Thr385, and Met524 in TMEM16A are critical for evodiamine and rutecarpine's inhibitory effects. Further functional studies show that both evodiamine and rutecarpine can significantly suppress the peristalsis in isolated guinea-pig ileum. These findings demonstrate that evodiamine and rutecarpine are new TMEM16A inhibitors and support the regulation effect of TMEM16A modulators on gastrointestinal motility.

Mechanisms Underlying the Cardioprotection of YangXinDingJi Capsule against Myocardial Ischemia in Rats.

BACKGROUND: YangXinDingJi (YXDJ) capsule is one of traditional Chinese medicines (TCMs) derived from Zhigancao decoction, which is usually used for the treatment of cardiovascular disease in China. Aim of the Study. Cardiovascular events are one of the leading causes of death worldwide. Myocardial ischemia (MI) severely reduces myocyte longevity and function. The YangXinDingJi (YXDJ) capsule has been used in the treatment of clinical cardiac disease in China. Nevertheless, the underlying cellular mechanisms for the benefits to heart function resulting from the use of this capsule are still unclear. The aim of this study was to evaluate the protective effects of the YXDJ on isoprenaline-induced MI in rats and to clarify its underlying myocardial protective mechanisms based on L-type calcium channels and myocardial contractility. MATERIALS AND METHODS: Rats were randomly divided into five groups with ten rats in each group: (1) control; (2) ISO-induced model; (3) high-dose YXDJ (2.8 g/kg/day intraperitoneally for five days), (4) low-dose YXDJ (1.4 g/kg/day for five days); and (5) verapamil (n = 10 in each group). Isoproterenol (ISO) was injected subcutaneously for two consecutive days to induce the rat model of MI. Heart and biochemical parameters were obtained. The patch-clamp technique was used to observe the regulatory effects of YXDJ on the L-type calcium current (ICa-L) in isolated cardiomyocytes. An IonOptix MyoCam detection system was used to observe the contractility of YXDJ on isolated cardiomyocytes. RESULTS: YXDJ caused a significant improvement in pathological heart morphology and alleviated oxidative stress and inflammatory responses. Exposure to YXDJ caused a decrease in blockade of ICa-L in a concentration-dependent manner. CONCLUSIONS: The results indicate that YXDJ significantly inhibited inflammatory cytokine expressions, oxidative stress, and L-type Ca2+ channels, and decreased contractility in isolated rat cardiomyocytes. These findings may be relevant to the cardioprotective efficacy of YXDJ.

Safranal, an active constituent of saffron, ameliorates myocardial ischemia via reduction of oxidative stress and regulation of Ca2+ homeostasis.

Safranal (SFR) is the major constituent of saffron. The purpose of this study was to observe the effect of SFR on myocardial ischemia induced by isoprenaline (ISO) and to explore its possible mechanism. The myocardial ischemia rat model was established by subcutaneous injection of ISO (85 mg/kg/d) on the 8th and 9th day of the experiment. Serum creatine kinase (CK), lactate dehydrogenase (LDH), malondialdehyde (MDA) and superoxide dismutase (SOD) were measured, as were changes in calcium concentration, reactive oxygen species (ROS) and cardiac morphology of the myocardial tissue. The effects of SFR on cell contraction, Ca2+ transient and L-type Ca2+ current (ICa-L) in isolated rat myocardial cells were measured using the Ion Optix detection system and the whole-cell patch-clamp technique. SFR can decrease the activity of serum CK, LDH and MDA, and increase the activity of serum SOD, reduce intracellular calcium concentration and the manufacture of ROS. In addition, SFR can improve changes in heart morphology. SFR can significantly inhibit contraction, Ca2+ transients and ICa-L in isolated ventricular myocytes. SFR has a cardioprotective role in ISO-induced MI rats, and the underling mechanism is related to the inhibition of oxidative stress, myocardial contractility, ICa-L and the regulation of Ca2+ homeostasis.

6-Gingerol, an active pungent component of ginger, inhibits L-type Ca2+ current, contractility, and Ca2+ transients in isolated rat ventricular myocytes.

Ginger has been widely used as a flavor, food, and traditional medicine for centuries. 6-Gingerol (6-Gin) is the active components of ginger and offers some beneficial effects on cardiovascular diseases. Here, the effects of 6-Gin on L-type Ca2+ current (ICa-L), contractility, and the Ca2+ transients of rat cardiomyocytes, were investigated via patch-clamp technique and the Ion Optix system. The 6-Gin decreased the ICa-L of normal and ischemic ventricular myocytes by 58.17 ± 1.05% and 55.22 ± 1.34%, respectively. 6-Gin decreased ICa-L in a concentration-dependent manner with a half-maximal inhibitory concentration (IC50) of 31.25 µmol/L. At 300 µmol/L, 6-Gin reduced the cell shortening by 48.87 ± 5.44% and the transients by 42.5 ± 9.79%. The results indicate that the molecular mechanisms underlying the cardio-protective effects of 6-Gin may because of a decreasing of intracellular Ca2+ via the inhibition of ICa-L and contractility in rat cardiomyocytes.