There is significant evidence that, in living systems, free radicals and other reactive oxygen and nitrogen species play a double role, because they can cause oxidative damage and tissue dysfunction and serve as molecular signals activating stress responses that are beneficial to the organism. Mitochondria have been thought to both play a major role in tissue oxidative damage and dysfunction and provide protection against excessive tissue dysfunction through several mechanisms, including stimulation of opening of permeability transition pores. Until recently, the functional significance of ROS sources different from mitochondria has received lesser attention. However, the most recent data, besides confirming the mitochondrial role in tissue oxidative stress and protection, show interplay between mitochondria and other ROS cellular sources, so that activation of one can lead to activation of other sources. Thus, it is currently accepted that in various conditions all cellular sources of ROS provide significant contribution to processes that oxidatively damage tissues and assure their survival, through mechanisms such as autophagy and apoptosis.

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Role of ROS and RNS Sources in Physiological and Pathological Conditions

In this review, we present the basic properties, physiological functions, regulation, and pathological alterations of four major classes of K+ channels that have been detected in vascular smooth muscle cells. Voltage-dependent K+ (Kv) channels open upon depolarization of the plasma membrane in vascular smooth muscle cells. The subsequent efflux of K+ through the channels induces repolarization to the resting membrane potential. Changes in the intracellular Ca2+ concentration and membrane depolarization stimulate large-conductance Ca2+-activated K+ (BKCa) channels, which are thought to play an important role in maintaining the membrane potential. ATP-sensitive K+ (K(ATP)) channels underscore the functional bond between cellular metabolism and membrane excitability. The blockade of KATP channel function results in vasoconstriction and depolarization in various types of vascular smooth muscle. Inward rectifier K+ (Kir) channels, which are expressed in smooth muscle of the small-diameter arteries, contribute to the resting membrane potential and basal tone. Kir channel activation has been shown to raise the extracellular K+ concentration to 10-15 mM, resulting in vasodilation. Each of K+ channels listed above is responsive to a number of vasoconstrictors and vasodilators, which act through protein kinase C (PKC) and protein kinase A (PKA), respectively. Impaired Kv, KATP, and Kir channel functions has been linked to a number of pathological conditions, which may lead to vasoconstriction.

Physiological roles of K^+ channels in vascular smooth muscle cells(Hirosi Kuriyama Award 2007 Memorial Review)

ATP-sensitive potassium (KATP) channels are present in the surface and internal membranes of cardiac, skeletal, and smooth muscle cells and provide a unique feedback between muscle cell metabolism and electrical activity. In so doing, they can play an important role in the control of contractility, particularly when cellular energetics are compromised, protecting the tissue against calcium overload and fiber damage, but the cost of this protection may be enhanced arrhythmic activity. Generated as complexes of Kir6.1 or Kir6.2 pore-forming subunits with regulatory sulfonylurea receptor subunits, SUR1 or SUR2, the differential assembly of KATP channels in different tissues gives rise to tissue-specific physiological and pharmacological regulation, and hence to the tissue-specific pharmacological control of contractility. The last 10 years have provided insights into the regulation and role of muscle KATP channels, in large part driven by studies of mice in which the protein determinants of channel activity ...

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Muscle KATP Channels: Recent Insights to Energy Sensing and Myoprotection

Vascular tone of resistance arteries and arterioles determines peripheral vascular resistance, contributing to the regulation of blood pressure and blood flow to, and within the body's tissues and organs. Ion channels in the plasma membrane and endoplasmic reticulum of vascular smooth muscle cells (SMCs) in these blood vessels importantly contribute to the regulation of intracellular Ca2+ concentration, the primary determinant of SMC contractile activity and vascular tone. Ion channels provide the main source of activator Ca2+ that determines vascular tone, and strongly contribute to setting and regulating membrane potential, which, in turn, regulates the open-state-probability of voltage gated Ca2+ channels (VGCCs), the primary source of Ca2+ in resistance artery and arteriolar SMCs. Ion channel function is also modulated by vasoconstrictors and vasodilators, contributing to all aspects of the regulation of vascular tone. This review will focus on the physiology of VGCCs, voltage-gated K+ (KV) channels, large-conductance Ca2+-activated K+ (BKCa) channels, strong-inward-rectifier K+ (KIR) channels, ATP-sensitive K+ (KATP) channels, ryanodine receptors (RyRs), inositol 1,4,5-trisphosphate receptors (IP3Rs), and a variety of transient receptor potential (TRP) channels that contribute to pressure-induced myogenic tone in resistance arteries and arterioles, the modulation of the function of these ion channels by vasoconstrictors and vasodilators, their role in the functional regulation of tissue blood flow and their dysfunction in diseases such as hypertension, obesity, and diabetes. © 2017 American Physiological Society. Compr Physiol 7:485-581, 2017.

Smooth Muscle Ion Channels and Regulation of Vascular Tone in Resistance Arteries and Arterioles.

Honey is a popular natural food product with a very complex composition mainly consisting of both organic and inorganic constituents. The composition of honey is strongly influenced by both natural and anthropogenic factors, which vary based on its botanical and geographical origins. Although minerals and heavy metals are minor constituents of honey, they play vital role in determining its quality. There are several different analytical methods used to determine the chemical elements in honey. These methods are typically based on spectroscopy or spectrometry techniques (including atomic absorption spectrometry, atomic emission spectrometry, inductively coupled plasma mass spectrometry, and inductively coupled plasma optical emission spectrometry). This review compiles available scientific information on minerals and heavy metals in honey reported from all over the world. To date, 54 chemical elements in various types of honey have been identified and can be divided into 3 groups: major or macroelements (Na, K, Ca, Mg, P, S, Cl), minor or trace elements (Al, Cu, Pb, Zn, Mn, Cd, Tl, Co, Ni, Rb, Ba, Be, Bi, U, V, Fe, Pt, Pd, Te, Hf, Mo, Sn, Sb, La, I, Sm, Tb, Dy, Sd, Th, Pr, Nd, Tm, Yb, Lu, Gd, Ho, Er, Ce, Cr, As, B, Br, Cd, Hg, Se, Sr), and heavy metals (trace elements that have a specific gravity at least 5 times higher than that of water and inorganic sources). Chemical elements in honey samples throughout the world vary in terms of concentrations and are also influenced by environmental pollution.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/1541-4337.12182

Physicochemical Properties, Minerals, Trace Elements, and Heavy Metals in Honey of Different Origins: A Comprehensive Review

A low-taurine diet during fetal or early postnatal life causes abnormal pancreatic β-cell development. Tissue and plasma taurine concentrations can also be low in diabetic patients. We examined the...

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Jin Han

Papers

Physiological roles of K^+ channels in vascular smooth muscle cells(Hirosi Kuriyama Award 2007 Memorial Review)

Taurine increases glucose sensitivity of UCP2-overexpressing β-cells by ameliorating mitochondrial metabolism

Role of Stretch-activated Channels in the Heart: Action Potential and Ca2+ Transients

Effect of Cyclic GMP on the Calcium Current in Rabbit Ventricular Myocytes

mesenchymal stem cells -treated human adipose-derived 1 β channels in TGF- Functional expression of smooth muscle-specific ion