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We have examined the effects of two DTX homologues, toxin I and toxin K, on Kv1.1, Kv1.2 and Kv1.6 channels expressed in Xenopus oocytes. Toxin I blocked all three channels; in contrast, toxin K was selective for Kv1.1. Both toxins slowed channel activation and inactivation kinetics with 10 nM toxin I approximately doubling activation and inactivation time(More)
The effects of cysteine-modifying reagents on the gating of rat cloned Kv1.4 channels expressed in HEK-293 cells were examined using the whole-cell patch-clamp technique. Cells transfected with Kv1.4 expressed a rapidly inactivating K+ current with a mid-point of activation of -31 mV and a slope factor of 5 mV measured with tail current protocols in 35 mM(More)
The effects of the polyunsaturated fatty acid, docosahexaenoic acid, were examined on two single cloned potassium channels, mKv1.1 and mKv1.2, stably expressed in Chinese hamster ovary cells using whole-cell patch clamp techniques. Docosahexaenoic acid produced a time- and dose-dependent, reversible block of mKv1.1 and mKv1.2. Interestingly, docosahexaenoic(More)
BACKGROUND Patients often do not get the information they require from doctors and nurses. To address this problem, interventions directed at patients to help them gather information in their healthcare consultations have been proposed and tested. OBJECTIVES To assess the effects on patients, clinicians and the healthcare system of interventions which are(More)
We have characterized tamulustoxin, a novel 35-amino-acid peptide found in the venom of the Indian red scorpion (Mesobuthus tamulus). Tamulustoxin was identified through a [125I]toxin I screen, designed to identify toxins that block voltage-activated potassium channels. Tamulustoxin has also been cloned by RT-PCR, using RNA extracted from scorpion venom(More)
1. Intracellular recordings from cultured rat spinal cord neurones demonstrated that Cl(-)-dependent responses to GABA (gamma-aminobutyric acid) (but not glycine) were increased in amplitude and duration by the steroid anaesthetic alphaxalone (3 alpha-hydroxy-5 alpha-pregnane-11,20-dione) at submicromolar concentrations that produced little or no effect on(More)
The coexpression of the rat Kv beta 1 subunit with the mouse Kv1.1 (mKv1.1) K+ channel in Chinese hamster ovary cells caused an increase in the rate of inactivation of whole-cell current. Current decayed in a bi-exponential fashion with a fast voltage-dependent and a slower voltage-independent component. The inactivating current component accounted for(More)
Case studies of the solid-phase synthesis of some 'difficult sequences' using continuous-flow Fmoc-polyamide techniques are presented. Solvent change and peptide side chain and backbone modification procedures recently found to reduce association effects are applied, and the results compared to syntheses under standard conditions.
Long-lasting conductance changes triggered either by brief (millisecond) electrical stimuli and/or entry of calcium ions have been observed in a variety of excitable tissues. The electrical consequences of these events depend on the ion conductance affected and on the ion concentration gradient across the membrane, while the long-lasting nature of the(More)