In an earlier investigation, we demonstrated that the likelihood of interaction of a positively charged ryanoid, 21-amino-9alpha-hydroxyryanodine, with the sarcoplasmic reticulum Ca(2+)-release channel (ryanodine receptor, RyR) is dependent on holding potential (Tanna, B., W. Welch, L. Ruest, J.L. Sutko, and A. J. Williams. 1998. J. Gen. Physiol. 112:55-69) and suggested that voltage dependence...

Plasma membrane voltage is a fundamentally important property of a living cell; its value is tightly coupled to membrane transport, the dynamics of transmembrane proteins, and to intercellular communication. Accurate measurement of the membrane voltage could elucidate subtle changes in cellular physiology, but existing genetically encoded fluorescent voltage reporters are better at reporting re...

Large conductance voltage- and Ca(2+)-activated K(+) (BK(Ca)) channels regulate important physiological processes such as neurotransmitter release and vascular tone. BK(Ca) channels possess a voltage sensor mainly represented by the S4 transmembrane domain. Changes in membrane potential displace the voltage sensor, producing a conformational change that leads to channel opening. By site-directe...

Inward rectifier K(+) channels (Kir2.1) exhibit an extraordinary rectifying feature in the current-voltage relationship. We have previously showed that the bundle-crossing region of the transmembrane domain constitutes the crucial segment responsible for the polyamine block. In this study, we demonstrated that the major blocking effect of intracellular Mg(2+) on Kir2.1 channels is also closely ...

Voltage-gated ion channels derive their voltage sensitivity from the movement of specific charged residues in response to a change in transmembrane potential. Several studies on mechanisms of voltage sensing in ion channels support the idea that these gating charges move through a well-defined permeation pathway. This gating pathway in a voltage-gated ion channel can also be mutated to transpor...

Large-conductance, voltage-, and Ca(2+)-sensitive K(+) (maxi-K(Ca)) channels regulate neuronal and smooth muscle excitability. Their pore-forming alpha-subunit shows similarities with voltage-gated channels and indeed can open in the practical absence of Ca(2+). The NH(2) terminus is unique, with a seventh transmembrane segment involved in beta-subunit modulation. The long COOH terminus is impl...

This paper represents the performance of a squirrel-cage High Temperature Superconducting Induction/ Synchronous Motor (HTS-ISM) based on nonlinear electrical equivalent circuit. The structure of the HTS-ISM is the same as that of the squirrel-cage type induction machine, and the secondary windings are fabricated by the use of the HTS wires. It has already been shown that based on the experimen...