Cl(-) channel has been identified in heart over more than a decade. It is now known that Cl(-) channel is a super-family. The potentially important roles of cardiac Cl(-) channels have been emerging. Cardiac Cl(-) channels may play multifunctional roles in both physiological and pathophysiological conditions. Since the existence and distribution of cardiac Cl(-) channels vary with species and cardiac tissues, and blockade of Cl (-) channel with putative Cl(-) channel blockers or Cl(-) substitution has profound influence on cardiac electrical properties, it appears that the main role of cardiac Cl(-) channels may be to modulate cation channels or provide an ionic environment suitable for the activities of cation channels. So, to investigate the relationship between Cl(-) channels and cation channels may be of physiological and pathophysiological significance.
Animals ; Calcium Channels ; physiology ; Cations ; metabolism ; Chloride Channels ; physiology ; Heart ; physiology ; Humans ; Potassium Channels ; physiology ; Sodium Channels ; physiology ; TRPM Cation Channels ; physiology

Inwardly rectifying potassium channels (Kir) are a special subset of potassium selective ion channels which pass potassium more easily into rather than out of the cell. These channels mediate a variety of cellular functions, including control of membrane resting potential, maintenance of potassium homeostasis and regulation of cellular metabolism. Given the existence of fifteen Kir genes in mammals, current genetic studies using mutant animals that lack a single channel may have missed many important physiological functions of these channels due to gene redundancy. This issue can be circumvented by using a simple model organism like Drosophila, whose genome encodes only 3 Kir proteins. The sophisticated genetic approaches of Drosophila may also provide powerful tools to identify additional regulation mechanisms of Kir channels. Here we provide an overview of the progress made in elucidating the function of Drosophila Kir channels. The knowledge of Drosophila Kir channels may lead us to uncover novel functions and regulation mechanisms of human Kir channels and help on pathological studies of related diseases.
Animals ; Drosophila ; physiology ; Membrane Potentials ; Potassium ; physiology ; Potassium Channels, Inwardly Rectifying ; physiology

K(+) channels form a large family of membrane proteins that are expressed in a polarized fashion in any epithelial cell. Based on the transmembrane gradient for K(+) that is maintained by the Na(+)-K(+)-ATPase, these channels serve two principal functions for transepithelial transport: generation of membrane voltage and recycling of K(+). In this brief review, we will outline the importance of this ancient principle by examples of epithelial transport in the renal proximal tubule and gastric parietal cells. In both tissues, K(+) channel activity is rate-limiting for transport processes across the epithelial cells and essential for cell volume regulation. Recent experimental data using pharmacological tools and genetically modified animals have confirmed the original physiological concepts and specified the knowledge down to the molecular level. The development of highly active and tissue selective small molecule therapeutics has been impeded by two typical features of K(+) channels: their molecular architecture challenges the design of molecules with high affinity binding and they are expressed in a variety of tissues at the same time. Nevertheless, new insights into pathophysiology, e.g. that K(+) channel inhibition can block gastric acid secretion, render the clinical use of K(+) channel drugs in gastric disease and as kidney transport inhibitors highly attractive.
Animals ; Biological Transport ; Epithelial Cells ; physiology ; Kidney ; physiology ; Potassium ; Potassium Channels ; physiology ; Sodium-Potassium-Exchanging ATPase ; physiology

Animals ; Asthma ; physiopathology ; Bronchi ; metabolism ; Bronchial Hyperreactivity ; etiology ; Humans ; Muscle, Smooth ; metabolism ; Potassium Channels ; chemistry ; physiology ; Potassium Channels, Calcium-Activated ; physiology ; Potassium Channels, Voltage-Gated ; physiology

The mathematical models for simulation of cardiac sodium, potassium and calcium channel kinetics courses and currents were developed to simulate the properties of ionic currents and channel dynamic courses. With modifications of these models, it is possible to make them integrated for simulating the whole process of action potential, thus additional discussion on ionic mechanism could provide a theoretical foundation for further animal experiments and clinical applications.
Action Potentials ; Algorithms ; Calcium Channels ; physiology ; Computer Simulation ; Ion Channels ; physiology ; Membrane Potentials ; Models, Cardiovascular ; Myocytes, Cardiac ; physiology ; Potassium Channels ; physiology ; Sodium Channels ; physiology

Recently, more and more studies have discovered that some diseases result from gene defect and functional variation of ion channels, which are called ion passage diseases or ion channelopathies. Meanwhile, it has been found that even though many diseases do not fall into the category of the ion passage disease, some links or passages during the disease development are closely related with the malfunction of ion channels, and many drugs can prevent and cure these diseases by acting on ion channels. Therefore, the relationship between physiology/pathophysiology and ion channels is gradually becoming one of the hot topics in the current researches. The recent progress in the researches on the relationship between penile erection and ion channels is briefly reviewed in this article.
Calcium Channels ; physiology ; Chloride Channels ; physiology ; Connexin 43 ; genetics ; Erectile Dysfunction ; etiology ; Humans ; Ion Channels ; physiology ; Male ; Penile Erection ; physiology ; Potassium Channels ; physiology

Humans ; Potassium Channels, Inwardly Rectifying ; chemistry ; classification ; physiology ; Potassium Channels, Tandem Pore Domain ; chemistry ; classification ; physiology ; Protein Structure, Tertiary

The regulation of vascular and trabecular smooth muscle relaxation or contraction in the penis, that is, the physiology of corporal smooth muscle tone, determines penile erection or flaccidity. There is considerable evidence that the potassium channel and calcium channel, like many other vascular tissues, are the major modulators of smooth muscle tone in the corpora. Moreover, data on cultured corporal smooth muscle cells and isolated corporal tissue strips have demonstrated that the neurotransmitters participating in erection modulate corporal smooth muscle tone largely through their effects on ionic channels and transmembrane ionic flux.
Cell Line ; Humans ; Ion Channels ; physiology ; Male ; Muscle Contraction ; physiology ; Muscle, Smooth ; cytology ; physiology ; Penis ; cytology ; physiology ; Potassium Channels ; physiology ; Sodium Channels ; physiology

Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels in vertebrate are reverse voltage-dependent, and its activation depends on the hyperpolarization of cell and may be directly or indirectly regulated by the cyclic adenosine monophosphate (cAMP) or other signal transduction cascades. The distribution, quantity, and activation states of HCN channels differ in tissues throughout the body. By modulating If/If current, HCN channels may influence the resting membrane potential, and thus importantly regulate neuronal excitability, dendritic integration of synaptic potentials, and synaptic transmission. Evidence exhibits that HCN channels participate in pain and other physiological and pathological process. Pharmacological treatment targeting HCN channels is of benefit to relieve pain and other related diseases.
Humans ; Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels ; physiology ; Membrane Potentials ; Pain ; physiopathology ; Potassium Channels ; Synaptic Transmission

Cell Line ; Cyclic Nucleotide-Gated Cation Channels ; physiology ; Humans ; Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels ; Ion Channels ; physiology ; Membrane Potentials ; Muscle Proteins ; physiology ; Potassium Channels