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...

MOTIVATION Potassium channels are mainly known for their role in regulating and maintaining the membrane potential. Since this is one of the key mechanisms of signal transduction, malfunction of these potassium channels leads to a wide variety of severe diseases. Thus potassium channels are priority targets of research for new drugs, despite the fact that this protein family is highly variable ...

A spike that is the result of calcium permeability through potassium channels was separated from the action potential is squid giant axons internally perfused with a 30 mM NaF solution and bathed in a 100 mM CaCl2 solution by blocking sodium channels with tetrodotoxin. Currents through potassium channels were studied under voltage clamp. The records showed a clear voltage-dependent inactivation...

Within the Caenorhabditis elegans genome there exist at least 42 genes encoding TWK (two-P domain K(+)) channels, potassium channel subunits that contain two pore regions and four transmembrane domains. We now report the first functional characterization of a TWK channel from C. elegans. Although potassium channels have been reported to be activated by a variety of factors, TWK-18 currents incr...

Small conductance calcium-activated potassium channels show a distinct pharmacology. Some, but not all, are blocked by the peptide toxin apamin, and apamin-sensitive channels are also blocked by d-tubocurarine. Cloned SK channels (small conductance calcium-activated potassium channel) recapitulate these properties. We have investigated the structural basis for these differences and found that t...