Effect of wine polyphenol resveratrol on the contractions elicited electrically or by norepinephrine in the rat portal vein

The roles of melatonin and potassium channels in relaxation response to ang 1-7 in diabetic rat isolated aorta

In a circadian cycle, the pineal gland produces and releases melatonin (MEL) into the bloodstream. By activating distinct melatonin receptors, MEL has been shown to variably change vascular endothelial dysfunction (VED) to various vascular beds. This study investigates the interaction of melatonin (MEL) and potassium ion (K+) on angiotensin 1-7 (Ang 1-7) vasorelaxant in streptozotocin (STZ)-induced diabetes mellitus (DM) and non-diabetes mellitus (non-DM) male albino rat aortic rings. The isometric tension of isolated aortic rings was assessed by generating a dose-response curve (DRC) for Ang 1-7 using a PowerLab data acquisition system. Accordingly, three experimental sets were carried out. In the first set the aortic rings were exposed MEL and MEL agonist ramelteon (RAM) and MEL antagonist luzindole (LUZ). In the second set, the aortic rings were exposed to various non-selective calcium activated potassium channel (KCa) blockers, including tetraethylammonium (TEA), a small and large-conductance calcium-activated K+ [(SKCa) and (BKCa)] channels blocker charybdotoxin (ChTx) and intermediate calcium-activated K+ channel (IKCa) blocker clotrimazole (CLT). In the third set, the aortic rings were exposed to various selective K+ channels blockers, including the selective blocker of KATP channel, glibenclamide (Glib), 4-aminopyridine (4-AP), a selective blocker of Kv channels and BaCl2, delayed inward rectifier K+ channels (Kir) blocker. The results highlight the significant role of MEL in modulating vascular reactivity, particularly in the DM aorta. By enhancing the vasorelaxant effects of Ang 1-7 through mechanisms involving its receptors and antioxidant activities, MEL demonstrates its potential to counteract oxidative stress and VED associated with diabetes. These findings advance the understanding of vascular reactivity in diabetes and suggest MEL as a promising therapeutic agent for improving vascular health in diabetic conditions.

Histone Deacetylase Inhibitors: Providing New Insights and Therapeutic Avenues for Unlocking Human Birth

The pregnant uterus remains relaxed throughout fetal gestation before transforming to a contractile phenotype at term to facilitate birth. Despite ongoing progress, the precise mechanisms that regulate this phenotypic transformation are not yet understood. This knowledge gap limits our understanding of how dysregulation of uterine smooth muscle biology contributes to life-threatening obstetric complications, including preterm birth, and hampers our ability to develop effective therapeutic intervention strategies. Protein acetylation plays a vital role in regulating protein structure, function, and subcellular localization, as well as gene transcription availability through regulating chromatin condensation. Histone deacetylase inhibitors (HDACis) are a class of compounds that block the removal of acetyl functional groups from proteins and, as such, have profound effects on important cellular events, including phenotypic transformation. A large body of data now demonstrates that HDACis have profound effects on pregnant human myometrium. Studies to date show that HDACis operate through both genomic and non-genomic mechanisms to affect myometrial function and phenotype. Interestingly, the effects of HDACis on pregnant myometrium are largely "pro-relaxation," including the direct inhibition of contractile machinery as well as repression of pro-labor genes. The "dual action" effects of HDACis make them a powerful tool for unlocking the regulatory processes that underpin myometrial phenotypic transformation and raises prospects of their therapeutic applications. Here, we review the new insights into human myometrial biology that have garnered through the application of HDACis and explore their potential therapeutic application toward the development of novel preterm birth prevention strategies.

Cardioprotection stimulated by resveratrol and grape products prevents lethal cardiac arrhythmias in an animal model of ischemia and reperfusion

PURPOSE

To evaluate the preventive cardioprotective effects of resveratrol and grape products, such as grape juice and red wine, in animal model of cardiac ischemia and reperfusion.

METHODS

Male Wistar rats orally pretreated for 21-days with resveratrol and grape products were anesthetized and placed on mechanical ventilation to surgically induce cardiac ischemia and reperfusion by obstruction (ischemia) followed by liberation (reperfusion) of blood circulation in left descending coronary artery. These rats were submitted to the electrocardiogram (ECG) analysis to evaluate the effects of pretreatment with resveratrol and grape products on the incidence of ventricular arrhythmias (VA), atrioventricular block (AVB) and lethality (LET) resulting from cardiac ischemia and reperfusion.

RESULTS

It was observed that the incidence of AVB was significantly lower in rats pretreated with resveratrol (25%), grape juice (37.5%) or red wine (12.5%) than in rats treated with saline solution (80%) or ethanol (80%). Similarly, incidence of LET was also significantly lower in rats pretreated with resveratrol (25%), grape juice (25%) or red wine (0%) than in rats treated with saline solution (62.5%) or ethanol (75%).

CONCLUSIONS

These results indicate that the cardioprotective response stimulated by resveratrol and grape products prevents the lethal cardiac arrhythmias in animal model of ischemia and reperfusion, supporting the idea that this treatment can be beneficial for prevention of severe cardiac arrhythmias in patients with ischemic heart disease.

Potassium Channels as a Potential Target Spot for Drugs

Aberrant function or expression of potassium channels can be underlying in pathologies such as cardiac arrhythmia, diabetes mellitus, hypertension, preterm birth, and various types of cancer. The expression of potassium channels is altered in many types of diseases. Also, we have previously shown that natural polyphenols, such as resveratrol, and selective synthetic modulators of potassium channels, like pinacidil, can alter their function and lead to the desired outcome. Therefore, targeting potassium channels with substance, which has an influence on their function, is promising access to cancer, diabetes mellitus, preterm birth, or hypertension therapy. In this chapter, we could discuss strategies for targeting different types of potassium channels as potential targets for synthetic and natural molecules therapy.

Resveratrol and polydatin as modulators of Ca2+ mobilization in the cardiovascular system

In the cardiovascular system, Ca²⁺ controls cardiac excitation-contraction coupling and vascular contraction and dilation. Disturbances in intracellular Ca²⁺ homeostasis induce malfunctions of the cardiovascular system, including cardiac pump dysfunction, arrhythmia, remodeling, and apoptosis, as well as hypertension and impairment of vascular reactivity. Therefore, developing drugs and strategies manipulating Ca²⁺ handling are highly valued in the treatment of cardiovascular disease. Resveratrol (Res) and polydatin (PD), a Res glucoside, have been well established to have beneficial effects on improving cardiovascular function. Studies from our laboratory and others have demonstrated that they exhibit inotropic effects on normal heart and therapeutic effects on hypertension, cardiac ischemia/reperfusion injury, hypertrophy, and heart failure by manipulating Ca²⁺ mobilization. The actions of Res and PD on Ca²⁺ signals delicately manipulated by multiple Ca²⁺ -handling proteins are pleiotropic and somewhat controversial, depending on cellular species and intracellular oxidative status. Here, we focus on the effects of Res and PD on controlling Ca²⁺ homeostasis in the heart and vasculature under normal and diseased conditions and highlight the key direct and indirect molecules mediating these effects.

The Role of Potassium Channels in the Vasodilatation Induced by Resveratrol and Naringenin in Isolated Human Umbilical Vein

Preclinical Research Potassium (K⁺ ) channels have a key role in the maintenance of smooth muscle tone; a variety of agonists can modify the tone by altering K⁺ -channel activity. The aim of this study was assess the effects of the phenols, resveratrol, and naringenin on K⁺ -channels of the vascular smooth muscle. Segments of human umbilical vein (HUV) without endothelium were precontracted using serotonin (100 μM) or 100 mM K⁺ to derive cumulative concentration-response curves using increasing concentrations of resveratrol or naringenin. K⁺ -channel inhibitors were added in the bath before resveratrol (1-100 μM) or naringenin (0.01-1 mM) in assess the role of K⁺ -channels in their effects on HUV precontracted by serotonin. 4-Aminopiridine (4-AP; 1 mM), a nonselective blocker of voltage-dependent, tetraethylammonium (TEA; 1 mM) and barium chloride (1 mM), a nonselective blocker of Ca²⁺ -dependent and inward rectifier K⁺ -channels (respectively) induced significant shifts to the right (P < 0.05) of resveratrol. concentration-response curves. The effect of naringenin was antagonized by 4-AP (1 mM). 4-AP-, TEA-, and barium chloride-sensitive K⁺ -channels are probably involved in the resveratrol vasodilatatory effect, while naringenin seems to affect 4-AP-sensitive K⁺ -channels. However, other mechanisms of vasodilation induced by polyphenols could not be excluded. Drug Dev Res, 2015. © 2015 Wiley Periodicals, Inc.

Resveratrol and calcium signaling: molecular mechanisms and clinical relevance

Resveratrol is a naturally occurring compound contributing to cellular defense mechanisms in plants. Its use as a nutritional component and/or supplement in a number of diseases, disorders, and syndromes such as chronic diseases of the central nervous system, cancer, inflammatory diseases, diabetes, and cardiovascular diseases has prompted great interest in the underlying molecular mechanisms of action. The present review focuses on resveratrol, specifically its isomer trans-resveratrol, and its effects on intracellular calcium signaling mechanisms. As resveratrol's mechanisms of action are likely pleiotropic, its effects and interactions with key signaling proteins controlling cellular calcium homeostasis are reviewed and discussed. The clinical relevance of resveratrol's actions on excitable cells, transformed or cancer cells, immune cells and retinal pigment epithelial cells are contrasted with a review of the molecular mechanisms affecting calcium signaling proteins on the plasma membrane, cytoplasm, endoplasmic reticulum, and mitochondria. The present review emphasizes the correlation between molecular mechanisms of action that have recently been identified for resveratrol and their clinical implications.