The multitopic ion-pair receptor 2 is able to recognize and extract various cesium and potassium salts via three different ion recognition modes. Furthermore, it is capable of extracting and then releasing KNO(3)via ion-pair metathesis with CsClO(4), allowing KNO(3) recovery.

A literature review reveals many lines of evidence that both delayed rectifier and inward rectifier potassium channels are multi-ion pores. These include unidirectional flux ratios given by the 2--2.5 power of the electrochemical activity ratio, very steeply voltage-dependent block with monovalent blocking ions, relief of block by permeant ions added to the side opposite from the blocking ion, ...

The activation of voltage-dependent ion channels is initiated by potential-induced conformational rearrangements in the voltage-sensor domains that propagates to the pore domain (PD) and finally opens the ion conduction pathway. In potassium channels voltage-sensors are covalently linked to the pore via S4-S5 linkers at the cytoplasmic site of the PD. Transformation of membrane electric energy ...

Cesium uptake by sodium-loaded frog sartorius muscles was inhibited 100% by 10(-6)M ouabain and 10(-6)M cymarin. The doses for 50% inhibition of cesium uptake by five cardiotonic aglycones were 1.5 x 10(-6)M for strophanthidin, 2 x 10(-7)M for telocinobufagin, 1.6 x 10(-6) for digitoxigenin, 2.4 x 10(-6)M for periplogenin, and 6.3 x 10(-6)M for uzarigenin. Because of the limited solubility of s...

Current technologies for studying ion channels are fundamentally limited because of their inability to functionally link ion channel activity to cellular pathways. Herein, we report the use of label-free cell phenotypic profiling to decode the composition and signaling of an endogenous ATP-sensitive potassium ion channel (KATP) in HepG2C3A, a hepatocellular carcinoma cell line. Label-free cell ...

A trial fibrillation (AF) is the most common cardiac arrhythmia. The preferred therapy for AF is sustained sinus rhythm control; however, the efficacy of currently used antiarrythmic drugs is limited by adverse side effects resulting from both a lack of ion channel selectivity and nonspecific ventricular activity. The role of the voltage-gated potassium channels in atrial myocyte repolarization...

Potassium channels selectively conduct K(+) ions across cellular membranes with extraordinary efficiency. Their selectivity filter exhibits four binding sites with approximately equal electron density in crystal structures with high K(+) concentrations, previously thought to reflect a superposition of alternating ion- and water-occupied states. Consequently, cotranslocation of ions with water h...

Ion and oxygen uptake were studied on aging bean stem slices. Oxygen uptake was high immediately after slicing, decreased to a minimum at 100 minutes, and then increased again. Ion uptake per unit of O(2) uptake data suggested that metabolic energy was utilized almost exclusively for sodium transport in fresh tissue but was diverted to potassium transport as the slices aged. Oxygen and ion upta...

Ion channels play a key role in defining myometrial contractility. Modulation of ion channel populations is proposed to underpin gestational changes in uterine contractility associated with the transition from uterine quiescence to active labour. Of the myriad ion channels present in the uterus, this article will focus upon potassium channels encoded by the KCNQ genes and ether-à-go-go-related ...