Vascular relaxing effect of Hydrocotyle umbellata L. is mediated by blocking of l-type Ca2+ channels.

ETHNOPHARMACOLOGICAL RELEVANCE: Hydrocotyle umbellata L. is a medicinal herb for the treatment of some health problems including hypertension, according to traditional medicine. Even so, its vascular effects and the pharmacological action mechanisms have not been analyzed. AIM OF THE STUDY: This experiment aimed to analyze the effects of hydroalcoholic extract of Hydrocotyle umbellata L. (HEHU) on isolated vessels and verify the interaction of hibalactone (chemical marker) against Cav1.2 channels using molecular docking. MATERIALS AND METHODS: Vascular reactivity experiments were performed using rat aortas with (E+) or without endothelium (E-) in an isolated organ bath. Computational molecular docking approaches were used to show the direct effect on L-type Ca2+ Channels. RESULTS: HEHU (0-560 µg/mL) induced relaxation of the pre-contracted arteries in a concentration-dependent manner. The maximum effect was higher in E+ (76.8 ± 4.1%) as compared to E- (47.3 ± 5.5%). Pre-treatment of E+ arteries with L-NAME or ODQ reduced the relaxation to similar level of E- arteries. The treatment of arteries with MDL-12,330 A, diclofenac, propranolol and atropine did not change the relaxation induced by HEHU. The contraction caused by internal Ca2+ release induced by caffeine was reduced after HEHU treatment. Moreover, the HEHU also impaired the contraction induced by Ca2+ influx stimulated with phenylephrine or high KCl. The docking study demonstrated the effectiveness of hibalactone in blocking the Cav1.2 channel. CONCLUSIONS: These findings show that HEHU induces vascular relaxation which is potentiated (but not dependent) by endothelial cells. Blocking of Ca2+ influx seems to be the main mechanism for the vascular effects of HEHU.

Lacidipine Attenuates Symptoms of Nicotine Withdrawal in Mice.

Nicotine-withdrawal after daily exposure manifests somatic and affective symptom including a range of cognitive deficits. Earlier studies suggested participation of L-type calcium channels (LTCCs) in development of nicotine dependence and expression of withdrawal signs. An upsurge in Ca2+-induced oxidative stress in brain underlies the biochemical events and behavioral signs of nicotine-withdrawal. The present study is aimed to explore the effects of lacidipine (LTCC antagonist) against nicotine-withdrawal. Swiss albino mice were administered ( -)-nicotine hydrogen tartrate (3.35 mg/kg, t.i.d.) from days 1 to 7 and alongside lacidipine (0.3, 1, and 3 mg/kg, i.p.) given from days 1 to 14. Somatic withdrawal signs were noted 48 h after last dose of nicotine. Bay-K8644 (LTCC agonist) was administered in mice subjected to nicotine-withdrawal and lacidipine (3 mg/kg) treatments. Behavioral tests of memory, anxiety, and depression were conducted on days 13 and 14 to assess the effects of lacidipine on affective symptoms of nicotine-withdrawal. Biomarkers of oxido-nitrosative were quantified in the whole brain. Nicotine-withdrawal significantly enhanced somatic signs and symptoms of anxiety, depression, and memory impairment in mice. Lacidipine (1 and 3 mg/kg) attenuated nicotine-withdrawal induced somatic symptoms and also ameliorated behavioral abnormalities. Nicotine-withdrawal triggered an upsurge in brain lipid peroxidation, total nitrite content, and decline in antioxidants, and these effects were attenuated by lacidipine. Bay-K8644 significantly abolished improvement in somatic and affective symptoms, and antioxidant effects by lacidipine in mice subjected to nicotine-withdrawal. Lacidipine mitigated nicotine-withdrawal triggered somatic and affective symptoms owing to decrease in brain oxido-nitrosative stress.

The mechanisms of calcium mobilization by procyanidins, flavonols and flavonoids from Cecropia glaziovii Sneth in pulmonary endothelial cell cultures endorse its popular use as vasodilator phytomedicine.

The hypotensive and antihypertensive activities of the aqueous extract (AE) and butanolic fraction (ButF) isolated from Cecropia glaziovii Sneth have been demonstrated in previous studies in animal models. This study aimed to evaluate the molecular mechanism of action responsible for the vasodilatory effect of procyanidins, flavanols, and flavonoids found in C. glaziovii in endothelial cell culture. For this purpose, we analyzed the effect of procyanidin B2 and B3 compounds, catechin, epicatechin, orientin, isoorientin, and isovitexin in the mobilization of Ca2+ in rat endothelial cell cultures. Parallel associations with different antagonists were examined by considering the following in vivo hypotensive mechanisms: blockage of L-type calcium channels, action on ß-2 adrenergic receptors, and vasodilation via the nitric oxide pathway. All measurements of calcium mobilization were carried out by using the fluorescence measurement methodology in a Flexstation M3 spectrophotometer. The results indicate that some of the compounds have mixed actions, acting through different calcium mobilization pathways. The mobilization induced by such compounds significantly decreased when they were incubated with their corresponding antagonists. Taken together, our data suggest that the beneficial effects seen with the popular use of Cecropia glaziovii Sneth in pathological conditions, such as systemic arterial hypertension, seem to be related to the plant's hypotensive effect, very probably promoted by the actions of flavonols, flavonoids, and procyanidins, by different pathways of calcium mobilization.

Gut bacteria-derived 5-hydroxyindole is a potent stimulant of intestinal motility via its action on L-type calcium channels.

Microbial conversion of dietary or drug substrates into small bioactive molecules represents a regulatory mechanism by which the gut microbiota alters intestinal physiology. Here, we show that a wide variety of gut bacteria can metabolize the dietary supplement and antidepressant 5-hydroxytryptophan (5-HTP) to 5-hydroxyindole (5-HI) via the tryptophanase (TnaA) enzyme. Oral administration of 5-HTP results in detection of 5-HI in fecal samples of healthy volunteers with interindividual variation. The production of 5-HI is inhibited upon pH reduction in in vitro studies. When administered orally in rats, 5-HI significantly accelerates the total gut transit time (TGTT). Deciphering the underlying mechanisms of action reveals that 5-HI accelerates gut contractility via activation of L-type calcium channels located on the colonic smooth muscle cells. Moreover, 5-HI stimulation of a cell line model of intestinal enterochromaffin cells results in significant increase in serotonin production. Together, our findings support a role for bacterial metabolism in altering gut motility and lay the foundation for microbiota-targeted interventions.

Mechano-Pharmacological Testing of L-Type Ca2+ Channel Modulators via Human Vascular Celldrum Model.

BACKGROUND/AIMS: This study aimed to establish a precise and well-defined working model, assessing pharmaceutical effects on vascular smooth muscle cell monolayer in-vitro. It describes various analysis techniques to determine the most suitable to measure the biomechanical impact of vasoactive agents by using CellDrum technology. METHODS: The so-called CellDrum technology was applied to analyse the biomechanical properties of confluent human aorta muscle cells (haSMC) in monolayer. The cell generated tensions deviations in the range of a few N/m² are evaluated by the CellDrum technology. This study focuses on the dilative and contractive effects of L-type Ca2+ channel agonists and antagonists, respectively. We analyzed the effects of Bay K8644, nifedipine and verapamil. Three different measurement modes were developed and applied to determine the most appropriate analysis technique for the study purpose. These three operation modes are called, particular time mode" (PTM), "long term mode" (LTM) and "real-time mode" (RTM). RESULTS: It was possible to quantify the biomechanical response of haSMCs to the addition of vasoactive agents using CellDrum technology. Due to the supplementation of 100nM Bay K8644, the tension increased approximately 10.6% from initial tension maximum, whereas, the treatment with nifedipine and verapamil caused a significant decrease in cellular tension: 10nM nifedipine decreased the biomechanical stress around 6,5% and 50nM verapamil by 2,8%, compared to the initial tension maximum. Additionally, all tested measurement modes provide similar results while focusing on different analysis parameters. CONCLUSION: The CellDrum technology allows highly sensitive biomechanical stress measurements of cultured haSMC monolayers. The mechanical stress responses evoked by the application of vasoactive calcium channel modulators were quantified functionally (N/m²). All tested operation modes resulted in equal findings, whereas each mode features operation-related data analysis.

Coptisine, a protoberberine alkaloid, relaxes mouse airway smooth muscle via blockade of VDLCCs and NSCCs.

BACKGROUND/AIMS: Recently, effective and purified ingredients of traditional Chinese medicine (TCM) were extracted to play crucial roles in the treatment of pulmonary diseases. Our previous research focused on TCM drug screening aimed at abnormal airway muscle contraction during respiratory diseases. Coptisine, an effective ingredient extracted from bitter herbs has shown a series of antioxidant, antibacterial, cardioprotective and neuroprotective pharmacological properties. In the current study, we questioned whether coptisine could also participate in asthma treatment through relaxing abnormal contracted mouse airway smooth muscle (ASM). The present study aimed to characterize the relaxant effects of coptisine on mouse ASM and uncover the underlying molecular mechanisms. METHODS: To investigate the role of coptisine on pre-contracted mouse ASM, a series of biological techniques, including force measurement and patch-clamp experiments were employed. RESULTS: Coptisine was found to inhibit high K+ or acetylcholine chloride (ACh)-induced pre-contracted mouse tracheal rings in a dose-dependent manner. Further research demonstrated that the coptisine-induced mouse ASM relaxation was mediated by alteration of calcium mobilization via voltage-dependent L-type Ca2+ channels (VDLCCs) and non-selective cation channels (NSCCs). CONCLUSION: Our data showed that mouse ASM could be relaxed by coptisine via altering the intracellular Ca2+ concentration through blocking VDLCCs and NSCCs, which suggested that this pharmacological active constituent might be classified as a potential new drug for the treatment of abnormal airway muscle contraction.

Taurine-magnesium coordination compound, a potential anti-arrhythmic complex, improves aconitine-induced arrhythmias through regulation of multiple ion channels.

Taurine-magnesium coordination compound (TMCC) exhibits antiarrhythmic effects in cesium-chloride-and ouabain-induced arrhythmias; however, the mechanism underlying these effects on arrhythmia remains poorly understood. Here, we investigated the effects of TMCC on aconitine-induced arrhythmia in vivo and the electrophysiological effects of this compound in rat ventricular myocytes in vitro. Aconitine was used to induce arrhythmias in rats, and the dosages required to produce ventricular premature contraction (VPC), ventricular tachycardia (VT), ventricular fibrillation (VF), and cardiac arrest (CA) were recorded. Additionally, the sodium current (INa) and L-type calcium current (ICa,L) were analyzed in normal and aconitine-treated ventricular myocytes using whole-cell patch-clamp recording. In vivo, intravenous administration of TMCC produced marked antiarrhythmic effects, as indicated by the increased dose of aconitine required to induce VPC, VT, VF, and CA. Moreover, this effect was abolished by administration of sodium channel opener veratridine and calcium channel agonist Bay K8644. In vitro, TMCC inhibited aconitine-induced increases in INa and ICa,L. These results revealed that TMCC inhibited aconitine-induced arrhythmias through effects on INa and ICa,L.

Diallyl trisulfide regulates rat colonic smooth muscle contractions by inhibiting L-type calcium channel currents.

Diallyl trisulfide (DATS) is an active organosulfide component of allicin and has several beneficial effects, including antimicrobial, antioxidant, cardioprotective and anticancer effects. Few studies have shown the modulatory effect of DATS on L-type calcium channels in rat colonic smooth muscle cells and colonic motility. To investigate the modulatory effect of DATS on L-type calcium channels in rat colonic smooth muscle and colonic contraction, L-type calcium channel currents were recorded, and colonic contractility in longitudinal and circular smooth muscle strips was measured. DATS attenuated L-type calcium channel currents without affecting steady-state activation or inactivation kinetics and inhibited the spontaneous contractions of both longitudinal and circular smooth muscle strips dose-dependently. In conclusion, DATS has an inhibitory effect on the contractions of colonic muscle strips that is related to its regulation of L-type calcium channels.

Salidroside contributes to reducing blood pressure and alleviating cerebrovascular contractile activity in diabetic Goto-Kakizaki Rats by inhibition of L-type calcium channel in smooth muscle cells.

BACKGROUND: Vascular disease is a common and often severe complication in diabetes mellitus. Hyperglycemia and hypertension are considered to be two of the leading risk factors for vascular complications in diabetic patients. However, few pharmacologic agents could provide a combinational therapy for controlling hyperglycemia and blood pressure in diabetic patients at the same time. Salidroside (SAL) is the major active ingredient derived from Rhodiola. Recently, it has been reported that SAL have an obvious hypoglycemic effect in diabetes and show a beneficial activity in diabetic vascular dysfunction. However, it remains unknown whether or not SAL treatment could directly reduce blood pressure in diabetes. Furthermore, it is not clear what is the molecular mechanism underlying the vascular protection of SAL treatment in diabetes. METHODS: Male diabetic Goto-Kakizaki (GK) and non-diabetic control Wistar-Kyoto (WKY) rats were administrated with different dosages of SAL (50, 100 and 200 mg/kg/day) for 4 weeks. Contractile responsiveness of cerebral artery to KCl or 5-HT was investigated by Pressure Myograph System. The activity of CaL channel was investigated by recording whole-cell currents, assessing the expressions of CaL channel α1C-subunit and its downstream kinase, MLCK, at protein or mRNA levels. RESULTS: We showed that administration of 100 mg/kg/day SAL for 4 weeks not only lowered blood glucose, but also reduced blood pressure and alleviated cerebrovascular contractile activity in diabetic GK rats, which suggested that SAL treatment may provide a combinational therapy for lowering blood glucose and reducing blood pressure in diabetes at the same time. Furthermore, SAL treatment markedly inhibited the function and expression of CaL channel in cerebral VSMCs isolated from diabetic GK rats or when exposed to hyperglycemia condition, which may be the underlying mechanism responsible for the vascular protection of SAL in diabetes. CONCLUSIONS: The present study provided evidences that SAL contributes to reducing blood pressure and alleviating cerebrovascular contractile activity in diabetic GK rats by inhibition of CaL channel in smooth muscle cells, which may provide a novel approach to treat vascular complications in diabetic patients.

An integrated anti-arrhythmic target network of compound Chinese medicine Wenxin Keli revealed by combined machine learning and molecular pathway analysis [corrected].

Wenxin Keli (WK), a Chinese patent medicine, is known to be effective against cardiac arrhythmias and heart failure. Although a number of electrophysiological findings regarding its therapeutic effect have been reported, the active components and system-level characterizations of the component-target interactions of WK have yet to be elucidated. In the current study, we present the first report of a new protective effect of WK on suppressing anti-arrhythmic-agent-induced arrhythmias. In a model of isolated guinea pig hearts, rapid perfusion of quinidine altered the heart rate and prolonged the Q-T interval. Pretreatment with WK significantly prevented quinidine-induced arrhythmias. To explain the therapeutic and protective effects of WK, we constructed an integrated multi-target pharmacological mechanism prediction workflow in combination with machine learning and molecular pathway analysis. This workflow had the ability to predict and rank the probability of each compound interacting with 1715 target proteins simultaneously. The ROC value statistics showed that 97.786% of the values for target prediction were larger than 0.8. We applied this model to carry out target prediction and network analysis for the identified components of 5 herbs in WK. Using the 124 potential anti-arrhythmic components and the 30 corresponding protein targets obtained, an integrative anti-arrhythmic molecular mechanism of WK was proposed. Emerging drug/target networks suggested ion channel and intracellular calcium and autonomic nervous and hormonal regulation had critical roles in WK-mediated anti-arrhythmic activity. A validation of the proposed mechanisms was achieved by demonstrating that calaxin, one of the WK components from Gansong, dose-dependently blocked its predicted target CaV1.2 channel in an electrophysiological assay.

Spasmolytic effect of Jasonia glutinosa on rodent intestine.

INTRODUCTION: Jasonia glutinosa is an endemic plant species of the Iberian Peninsula and Southern France traditionally used in infusions as a spasmolytic; this plant is also known as "té de roca" (rock tea) but there is no scientific evidence about the effects of this plant. AIM: To evaluate the spasmolytic effect of rock tea. METHODS: We have studied the in vitro effect of a rock tea extract on rat duodenum spontaneous contractions and the in vivo effect on mice gastrointestinal transit. RESULTS: Rock tea extract reduced the spontaneous contractions of rat duodenal smooth muscle, inhibited KCl-induced contractions and blocked the contractions invoked by both extracellular Ca2+ and the agonist of L-type calcium channels Bay K8644. This inhibitory effect was similar to the one observed after the addition of the antagonist of L-type calcium channels verapamil. Rock tea did not modify gastrointestinal transit in healthy mice. However, after the treatment with dextran sulfate sodium, an inducer of colitis, rock tea extract reverted the increase in the gastrointestinal transit associated with this treatment. CONCLUSION: Rock tea extract relaxed duodenal smooth muscle via L-type calcium channels and normalized gastrointestinal transit in a model of colitis. These results may validate the traditional use of Jasonia glutinosa in patients with gastrointestinal alterations. Thus, rock tea may be used as a spasmolytic agent to treat gastrointestinal disorders.

Mechanisms underlying the cardioprotective effect of Salvianic acid A against isoproterenol-induced myocardial ischemia injury in rats: Possible involvement of L-type calcium channels and myocardial contractility.

ETHNOPHARMACOLOGICAL RELEVANCE: Salvianic acid A (SAA), which is the main water-soluble fraction in Radix Salviae Milthiorrhizae, has been widely applied for treating cardiovascular diseases in China. AIM OF THE STUDY: To explore the effects of SAA against myocardial ischemia injury induced by isoproterenol (ISO) in rats and to clarify its underlying myocardial protective mechanisms based on l-type calcium channels and myocardial contractility. MATERIALS AND METHODS: The myocardial ischemia injured rat model was induced by administering ISO (85mg/kg) subcutaneously at evenly spaced intervals throughout the day and night for 2 consecutive days. Serum cardiac biomarkers were analyzed, and heart tissues were isolated and prepared for histopathology assay. The regulatory effects of SAA on the L-type calcium current (ICa-L) in rat ventricular myocytes were observed by the patch clamp technique. The IonOptix Myocam detection system was used to observe the contractility of isolated rat ventricular myocytes. RESULTS: SAA significantly ameliorated changes in heart morphology and electrocardiographic patterns and reduced serum levels of creatine kinase and lactate dehydrogenase in the ISO-induced myocardial ischemia injured rat model. Meanwhile, SAA reduced ICa-L in a concentration-time dependent way with an IC50 of 1.47×10(-5)M, upshifted the current-voltage, activation, and inactivation curves of ICa-L, and significantly inhibited the amplitude of the cell shortening. CONCLUSIONS: These results indicate that SAA exhibits significant cardioprotective effects against the ISO-induced myocardial ischemia injury, potentially through inhibiting ICa-L and decreasing myocardial contractility.

New Findings on the Effects of Tannic Acid: Inhibition of L-Type Calcium Channels, Calcium Transient and Contractility in Rat Ventricular Myocytes.

Tannic acid (TA) is a group of water-soluble polyphenolic compounds that occur mainly in plant-derived feeds, food grains and fruits. Many studies have explored its biomedical properties, such as anticancer, antibacterial, antimutagenic, antioxidant, antidiabetic, antiinflammatory and antihypertensive activities. However, the effects of TA on the L-type Ca(2+) current (ICa-L) of cardiomyocytes remain undefined. The present study examined the effects of TA on ICa-L using the whole-cell patch-clamp technique and on intracellular Ca(2+) handling and cell contractility in rat ventricular myocytes with the aid of a video-based edge detection system. Exposure to TA resulted in a concentration- and voltage-dependent blockade of ICa-L, with the half maximal inhibitory concentration of 1.69 µM and the maximal inhibitory effect of 46.15%. Moreover, TA significantly inhibited the amplitude of myocyte shortening and peak value of Ca(2+) transient and increased the time to 10% of the peak. These findings provide new experimental evidence for the cellular mechanism of action of TA and may help to expand clinical treatments for cardiovascular disease.

Effect of Benidipine in Human Internal Mammary Artery and Clinical Implications.

BACKGROUND: Graft spasm remains challenging in coronary artery bypass grafting (CABG). Calcium antagonists are commonly used in patients with coronary artery disease. This study investigated the inhibitory effect of third-generation dihydropyridine calcium channel antagonist benidipine on the vasoconstriction induced by various vasoconstrictors in the human internal mammary artery (IMA). METHODS: Isolated human IMA rings (N = 65, taken from 37 patients undergoing CABG) were studied in a myograph in 2 ways: the relaxing effect of benidipine on vasoconstrictor-induced precontraction by KCl and U46619 and the depressing effect of benidipine at plasma concentrations on the contraction. Enzyme-linked immunosorbent assay (ELISA) was used to measure the change of the protein related to the L-type calcium channel. RESULTS: Benidipine caused more relaxation in KCl-contracted (86.7% ± 3.3%; n = 12) than in U46619-contracted (63.8% ± 5.3%; n = 8; p < 0.001) IMA rings. Pretreatment of IMA with plasma concentrations of benidipine (-6.92 log M) significantly depressed subsequent contraction by KCl (from 17.3 ± 2.7 mN to 7.4 ± 1.2 mN; n = 6; p < 0.05) but did not significantly affect the contraction caused by U46619. Benidipine also caused a decrease of caveolin (CaV)1.2 protein content (0.55 ± 0.02 versus 0.63 ± 0.02 mg/mL; p < 0.05). CONCLUSIONS: We conclude that in human IMA, the third-generation dihydropyridine calcium channel antagonist benidipine has a potent inhibitory effect on the vasoconstriction mediated by a variety of vasoconstrictors. Use of benidipine in patients undergoing CABG may provide vasorelaxant or antispastic effects in the grafts.

Nifedipine attenuation of abdominal aortic aneurysm in hypertensive and non-hypertensive mice: Mechanisms and implications.

Rupture of abdominal aortic aneurysm (AAA) is a lethal event. No oral medicine has been available to prevent or treat AAA. We have recently identified a novel mechanism of eNOS uncoupling by which AAA develops, in angiotensin II (Ang II) infused hyperphenylalaninemia 1 (hph-1) mice. Using this unique model we investigated effects on AAA formation of the L-type calcium channel blocker nifedipine, in view of the unclear relationship between hypertension and AAA, and unclear mechanisms of aneurysm protective effects of some blood pressure lowering drugs. Six-month old hph-1 mice were infused with Ang II (0.7 mg/kg/day) for 2 weeks, and fed nifedipine chow at two different doses (5 and 20 mg/kg/day). While the high dose of nifedipine reduced blood pressure, the lower dose had no effect. Interestingly, the incidence rate of AAA dropped from 71% to 7 and 12.5% for low and high dose nifedipine, respectively. Expansion of abdominal aorta, determined by ultrasound imaging, was abolished by both doses of nifedipine, which recoupled eNOS completely to improve NO bioavailability. Both also abrogated aortic superoxide production. Of note, Ang II activation of NADPH oxidase in vascular smooth muscle cells and endothelial cells, known to uncouple eNOS, was also attenuated by nifedipine. Although low dose was a sub-pressor while the high dose reduced blood pressure via inhibition of calcium channels, both doses were highly effective in preventing AAA by preserving eNOS coupling activity to eliminate sustained oxidative stress from uncoupled eNOS. These data demonstrate that oral treatment of nifedipine is highly effective in preserving eNOS function to attenuate AAA formation. Nifedipine may be used for AAA prevention either at low dose in AAA risk group, or at high dose in patients with co-existing hypertension.

In Vitro Early Safety Pharmacology Screening: Perspectives Related to Cardiovascular Safety.

In vitro screening for cardiovascular safety liabilities of novel drug candidates presents a challenge for the pharmaceutical industry. Such approaches rely on detecting pharmacologic effects on key components of complex integrated system early in drug discovery to define potential safety liabilities. Key to such studies are the concepts of hazard identification vs. risk assessment, drug specificity vs. selectivity, and an appreciation of the challenges faced when attempting to translate in vitro findings to preclinical in vivo as well as clinical effects. This chapter defines some key aspects of early safety pharmacology screening for cardiovascular liabilities, citing studies of two key depolarizing cardiac currents (fast sodium current and L-type calcium current) as examples linked to effects on cardiac conduction and repolarization.

Effects of total flavones from Acanthopanax senticosus on L-type calcium channels, calcium transient and contractility in rat ventricular myocytes.

Acanthopanax senticosus (Rupr. et Maxim.) Harms (AS), a traditional herbal medicine, has been widely used to treat ischemic heart disease. However, the underlying cellular mechanisms of its benefits to cardiac function remain unclear. The present study examined the effects of total flavones from AS (TFAS) on L-type Ca(2+) channel currents (ICa-L ) using the whole cell patch-clamp technique and on intracellular calcium ([Ca(2+) ]i ) handling and cell contractility in rat ventricular myocytes with the aid of a video-based edge-detection system. Exposure to TFAS resulted in a concentration- and voltage-dependent blockade of ICa-L , with the half-maximal inhibitory concentration (IC50 ) of 283.12 µg/mL and the maximal inhibitory effect of 36.49 ± 1.95%. Moreover, TFAS not only increased the maximum current in the current-voltage relationship but also shifted the activation and inactivation curves of ICa-L toward the hyperpolarizing direction. Meanwhile, TFAS significantly reduced amplitudes of myocyte shortening and [Ca(2+) ]i with an increase in the time to 10% of the peak (Tp) and a decrease in the time to 10% of the baseline (Tr). Thus, the cardioprotective effects of TFAS may be attributed mainly to the attenuation of [Ca(2+) ]i through the direct inhibition of ICa-L in rat ventricular myocytes and consequent negative effect on myocardial contractility.

Vitis labrusca extract effects on cellular dynamics and redox modulations in a SH-SY5Y neuronal cell model: a similar role to lithium.

Oxidative stress and calcium imbalance are consistently reported in bipolar disorder (BD). Polymorphism of voltage-dependent calcium channel, L type, alpha 1C subunit (CACNA1c), which is responsible for the regulation of calcium influx, was also shown to have a strong association with BD. These alterations can lead to a number of different consequences in the cell including production of reactive species causing oxidative damage to proteins, lipids and DNA. Lithium is the most frequent medication used for the treatment of BD. Despite lithium's effects, long-term use can result in many negative side effects. Therefore, there is an urgent need for the development of drugs that may have similar biological effects as lithium without the negative consequences. Moreover, polyphenols are secondary metabolites of plants that present multi-faceted molecular abilities, such as regulation of cellular responses. Vitis labrusca extract (VLE), a complex mixture of polyphenols obtained from seeds of winery wastes of V. labrusca, was previously characterized by our group. This extract presented powerful antioxidant and neuroprotective properties. Therefore, the ability of VLE to ameliorate the consequences of hydrogen peroxide (H2O2)-induced redox alterations to cell viability, intracellular calcium levels and the relative levels of the calcium channel CACNA1c in comparison to lithium's effects were evaluated using a neuroblastoma cell model. H2O2 treatment increased cell mortality through apoptotic and necrotic pathways leading to an increase in intracellular calcium levels and alterations to relative CACNA1c levels. VLE and lithium were found to similarly ameliorate cell mortality through regulation of the apoptotic/necrotic pathways, decreasing intracellular calcium levels and preventing alterations to the relative levels of CACNA1c. The findings of this study suggest that VLE exhibits protective properties against oxidative stress-induced alterations similar to that of lithium. These findings suggest that VLE may be an attractive potential candidate as a novel therapeutic agent for BD.

Salvia miltiorrhiza (Danshen) inhibits L-type calcium current and attenuates calcium transient and contractility in rat ventricular myocytes.

ETHNOPHARMACOLOGICAL RELEVANCE: Salvia miltiorrhiza (SM, Danshen), a traditional Chinese herbal drug, has been widely used for hundreds of years to treat coronary artery disease. MATERIALS AND METHODS: We studied the effects of SM on the L-type Ca(2+) current (ICa-L) with whole-cell patch-clamp technique in rat ventricular myocytes, and its influence on Ca(2+) transient and contractility using video-based edge detection and dual excitation fluorescence photomultiplier systems as well. RESULTS: Exposure to SM solution caused a concentration- and voltage-dependent blockade of ICa-L, and the dose of SM solution (10g/l) decreased the maximal inhibitory effect of 35.2±1.2%. However, SM solution did not significantly change the current-voltage relationship or reversal potential of ICa-L, nor did it altered the activation and inactivation gating properties of cardiac Ca(2+) channels. Meanwhile, SM decreased the amplitude of myocyte shortening and the peak value of Ca(2+) transient with a significant decrease in the time to 90% of the baseline (Tr), but the time to 10% of the peak (Tp) was not dramatically prolonged. CONCLUSIONS: The results indicated that SM significantly inhibited L-type Ca(2+) channels, decreased [Ca(2+)]i and contractility in adult rat cardiac myocytes. These findings may be relevant to the cardioprotective efficacy of SM.