background: k+ channel toxins are essential tools for the first purifications, analysis of subunit structures and brain localization of voltage-gated k+ (kv) channels. the effects of a lot of toxins on kv are not fully known. methods: using whole-cell patch clamping technique the action of a series of toxins on kv3.4 current in rat liver cells with expressed kv3.4 channels (rle) cloned cells wa...

Vascular smooth muscle (VSM) cells, endothelial cells (EC), and pericytes that form the walls of vessels in the microcirculation express a diverse array of ion channels that play an important role in the function of these cells and the microcirculation in both health and disease. This brief review focuses on the K+ channels expressed in smooth muscle and endothelial cells in arterioles. Microva...

The mobility of lectin receptors and of two types of ion channels was studied in skeletal muscles of the frog Rana temporaria. Lectin receptors were labeled with fluorescent derivatives of succinyl-concanavalin A (Con A) or wheat germ agglutinin (WGA), and their mobility was measured by fluorescence recovery after photobleaching. Of the receptors for WGA, approximately 53% were free to diffuse ...

Potassium channels are trans-membrane proteins, which selectively transport K+ ions across cell membranes and play a key role in regulating the physiology of excitability cells and signal transduction pathways. Bothutous Schach (BS) scorpion venom consists of several polypeptides that could modulate ion channels. In this study, the effects of BS crude venom on passive and active electrophysiolo...

Down-regulation of Kv4.3 K⁺ channels commonly occurs in multiple diseases, but the understanding of the regulation of Kv4.3 K⁺ channels and the role of Kv4.3 K⁺ channels in pathological conditions are limited. HEK (human embryonic kidney)-293T cells are derived from HEK-293 cells which are transformed by expression of the large T-antigen. In the present study, by comparing HEK-293 and HEK-293T ...

Follicular oocytes from Xenopus laevis contain K+ channels activated by members of the recently recognized class of vasorelaxants that include cromakalim and pinacidil and blocked by antidiabetic sulfonylureas, such as glibenclamide. These channels are situated on the adherent follicular cells and are not present in denuded oocytes. Cromakalim-activated K+ channels are also activated by increas...

Voltage-dependent K(+) channels in the apical dendrites of CA1 pyramidal neurones play important roles in regulating dendritic excitability, synaptic integration, and synaptic plasticity. Using cell-attached, voltage-clamp recordings, we found a large variability in the waveforms of macroscopic K(+) currents in the dendrites. With single-channel analysis, however, we were able to identify four ...

Using the patch-clamp technique, we have identified two types of Ca(2+)-activated K+ (K(Ca)) channels in the human leukemic T cell line. Jurkat. Substances that elevate the intracellular Ca2+ concentration ([Ca2+]i), such as ionomycin or the mitogenic lectin phytohemagglutinin (PHA), as well as whole-cell dialysis with pipette solutions containing elevated [Ca2+]i, activate a voltage-independen...

Variety of ion channels is present in plasma membrane of endothelial cells. These include the potassium channels such as Ca(2+)-activated K(+) channels, inwardly rectifying K(+) channels, voltage-dependent K(+) channels and also ATP-regulated K(+) channels. Due to an influence on the membrane potential they are important regulators of vascular tone by modulating endothelial calcium ions signali...