Optogenetic tools were originally designed to target specific neurons for remote control of their activity by light and have largely been built around opsin-based channels and pumps. These naturally photosensitive opsins are microbial in origin and are unable to mimic the properties of native neuronal receptors and channels. Over the last 8 years, photoswitchable tethered ligands (PTLs) have en...

The amplitude of an A-like potassium current (I(Kfast)) in identified cultured motor neurons isolated from the jellyfish Polyorchis penicillatus was found to be strongly modulated by extracellular potassium ([K(+)](out)). When expressed in Xenopus oocytes, two jellyfish Shaker-like genes, jShak1 and jShak2, coding for potassium channels, exhibited similar modulation by [K(+)](out) over a range ...

Shaker-type potassium channels play important roles in determining the electrical excitability of cells. The native channel complex is thought to be formed by four pore-forming alpha subunits that provide four interaction sites for auxiliary modulatory Kvbeta subunits. Because Kvbeta subunits possess diverse modulatory activities including either up-regulation or down-regulation of potassium cu...

OBJECTIVE Crohn's disease is a chronic inflammation of the gastrointestinal tract with an abnormal immune phenotype. We investigated how intracellular calcium kinetics of Th1 and Th2 lymphocytes alter upon specific inhibition of Kv1.3 and IKCa1 channels in pediatric Crohn's disease. STUDY DESIGN Blood was taken from 12 healthy and 29 Crohn's disease children. Of those, 6 were switched to infl...

We have used single-channel recording techniques to investigate the properties of sodium-activated potassium channels (KNa channels) in cultured rat olfactory bulb neurons, and in large neurons in the mitral cell layer of thin slices of olfactory bulb. Ion channels highly selective for potassium over sodium and chloride, and requiring 10-180 mM internal sodium (Nai) for their activation, were p...

T he sites in the central nervous system where inhaled anesthetics exert their clinical effects remain to be defined. During the past two decades, most investigators in the field have shifted away from a nonspecific plasma membrane lipid site of action towards direct interactions with membrane proteins or even globular proteins. Currently, favored targets include ligand-gated ion channels, such...

Scorpion toxins that block potassium channels and antimicrobial plant defensins share a common structural CSαβ-motif. These toxins contain a toxin signature (K-C4-X-N) in their amino acid sequence, and based on in silico analysis of 18 plant defensin sequences, we noted the presence of a toxin signature (K-C5-R-G) in the amino acid sequence of the Arabidopsis thaliana defensin AtPDF2.3. We foun...

Potassium channels allow for the passive movement of potassium ions across the cell membrane and are instrumental in controlling the membrane potential in all cell types. Quaternary ammonium (QA) compounds block potassium channels and have long been used to study the functional and structural properties of these channels. Here we describe the interaction between three symmetrical hydrophobic QA...

The cell-attached and excised patch configurations of the patch clamp technique were used to study stretch-activated ion channels in Muller glial cells that were obtained from postmortem adult human retinas and were maintained in culture. A stretch-activated channel permeable to monovalent and divalent cations was found. Ion channels of this type have not been demonstrated previously in glial c...