Abstract-Since the first description of the anatomical atrioventricular nodes (AVNs), a large number of studies have provided insights into the heterogeneity of the structure as well as a repertoire of ion channel proteins that govern this complex conduction pathway between the atria and ventricles. These studies have revealed the intricate organization of multiple nodal and nodal-like myocytes contributing to the unique electrophysiology of the AVN in health and diseases.On the other hand, information regarding the contribution of specific ion channels to the function of the AVN remains incomplete. We reason that the identification of AVN-specific ion channels may provide a more direct and rational design of therapeutic target in the control of AVN conduction in atrial flutter/fibrillation, one of the most common arrhythmias seen clinically. In this study, we took advantage of 2 genetically altered mouse models with overexpression or null mutation of 1 of a small conductance Ca 2ϩ -activated K ϩ channel isoform, SK2 channel, and demonstrated robust phenotypes of AVN dysfunction in these experimental models. Overexpression of SK2 channels results in the shortening of the spontaneous action potentials of the AVN cells and an increase in the firing frequency. On the other hand, ablation of the SK2 channel results in the opposite effects on the spontaneous action potentials of the AVN. Furthermore, we directly documented the expression of SK2 channel in mouse AVN using multiple techniques. The new insights may have important implications in providing novel drug targets for the modification of AVN conduction in the treatment of atrial arrhythmias. Key Words: K Ca 2.2 channel Ⅲ SK2 channel Ⅲ atrioventricular nodes T he atrioventricular node (AVN) is a highly specialized pacemaking tissue located at the junction of the right atrium and ventricle. Indeed, it is the only electrical connection between atria and ventricles and provides the critical delay between atrial and ventricular contraction to allow for proper atrial emptying before the start of the ventricular contraction. Pharmacological slowing of impulses across AVN is widely used clinically in atrial flutter/fibrillation to ensure physiological ventricular responses in these conditions. Previous studies have identified the roles of several distinct ion channels in the AVN function, 1-5 and recent work has begun to assemble an array of ion channel genes in the pacemaking tissues. 6 On the other hand, information regarding contribution of specific ion channels to the function of the AVN remains incomplete. We reason that the identification of AVN-specific ion channels may provide a more direct and rational design of therapeutic target in the control of AVN conduction in atrial flutter/fibrillation, one of the most common arrhythmias seen clinically.Specifically -activated K ϩ channels (SK or K Ca 2). 9 -13 SK channels are encoded by at least 3 distinct genes, namely KCNN1 (SK1), KCNN2 (SK2), and KCNN3 (SK3). 9,10,13 Here, we directly document the robust expres...

Obesity is a growing public health problem, which has now been considered as a pandemic non-communicable disease. However, the efficacy of several approaches for weight loss is limited and variable. Thus, alternative anti-obesity treatments are urgently warranted, which should be effective, safe, and widely available. Active compounds isolated from herbs are similar with the practice of Traditional Chinese Medicine, which has a holistic approach that can target to several organs and tissues in the whole body. Capsaicin, a major active compound from chili peppers, has been clearly demonstrated for its numerous beneficial roles in health. In this review, we will focus on the less highlighted aspect, in particular how dietary chili peppers and capsaicin consumption reduce body weight and its potential mechanisms of its anti-obesity effects. With the widespread pandemic of overweight and obesity, the development of more strategies for the treatment of obesity is urgent. Therefore, a better understanding of the role and mechanism of dietary capsaicin consumption and metabolic health can provide critical implications for the early prevention and treatment of obesity.