The understanding of the independent regulation of sodium and potassium by the kidney has remained elusive. Recent evidence now points to dissimilar regulatory mechanisms in ion handling, dependent on the presence of either aldosterone alone or angiotensin II with aldosterone among other factors. This review summarizes past and present information in an attempt to reconcile the current concepts...

We show that many Markov models of ion channel kinetics have globally attracting stable invariant manifolds, even when the Markov process is time dependent. The primary implication of this is that, since the dimension of the invariant manifold is often substantially smaller than the full master equation system, simulations of ion channel kinetics can be substantially simplified, with no approxi...

We employ recently revealed structural information for the potassium channel in molecular and Brownian dynamics simulations to investigate the physical mechanisms involved in the transport of ions across this channel. We show that ion selectivity arises from the ability of the channel protein to completely solvate potassium ions but not the smaller sodium ions. From energy and free energy pertu...

The effects of coenzyme Q10 (Co Q10) on potassium ion release, membrane potential and fluidity of rabbit red blood cells were studied. Co Q10 inhibited the increased potassium ion release induced by cetylamine or lysolecithin from the cells. Co Q10 slightly decreased the membrane potential monitored by changes in fluorescence intensity of cyanine dye, 3,3'-dipropyl-2,2'-thiodicarbocyanine iodid...

We report the quantification of partial ion insertion into individual 7,7,8,8-tetracyanoquinodimethane nanoparticles. It is shown that both potassium and sodium ions can be inserted into single TCNQ nanoparticles from aqueous solution. The extent of both potassium and sodium insertion into individual nanoparticles is quantitatively measured and shown to be partial and sodium ion shows a higher ...

Potential difference across the cell membrane and intracellular activity of the potassium ion in rat liver cells were measured simultaneously using double-barreled potassium ion-selective microelectrodes. Both potential difference across the membrane and K+ activity in liver cells were depressed after treatment with the antineoplastic agents mitomycin C and 5-Flourouracil Dry Syrup, suggesting ...

Motility on surfaces is an important mechanism for bacterial colonization of new environments. In this report, we describe detection of rapid surface motility in the wild-type Bacillus subtilis Marburg strain, but not in several B. subtilis 168 derivatives. Motility involved formation of rapidly spreading dendritic structures, followed by profuse surface colonies if sufficient potassium ion was...

Rat lenses were incubated for 24 hr in media with various concentrations of potassium and a constant concentration of sodium. The media were prepared by adding potassium chloride to a basic 300 mOsm TC-199 medium. Concentrations of potassium up to 100 mM were produced with a maximum osmolarity of 500 mOsm. The content of lens water remained constant in all media even though the content of potas...

An anomalous diffusion model for ion channel gating is put forward. This scheme is able to describe nonexponential, power-law-like distributions of residence time intervals in several types of ion channels. Our method presents a generalization of the discrete diffusion model by Millhauser, Salpeter, and Oswald [Proc. Natl. Acad. Sci. U.S.A. 85, 1503 (1988)] to the case of a continuous, anomalou...

Potassium ion (K) is the most abundant intracellular metal ion in the body and plays an important role in biological activities. Fabrication of K recognition and response smart materials is of both scientific and technological interests for various applications. Recently, our group have developed a series kinds of K-recognizable responsive smart materials based on 15-crown-5 as K recognizing re...