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Diphenyleneiodonium (DPI) and its analogues have been previously shown to react via a radical mechanism whereby an electron is abstracted from a nucleophile to form a radical, which then adds back to the nucleophile to form covalent adducts [Banks (1966) Chem. Rev. 66, 243-266]. We propose that the inhibition of neutrophil NADPH oxidase by DPI occurs via a(More)
NADPH-dependent superoxide production by the solubilized oxidase of neutrophils was inhibited 36% by diphenylene iodonium at a 1:1 stoichiometry with the enzyme flavoprotein content. Addition of diphenylene iodonium strongly inhibited the NADPH-dependent reduction of both FAD and cytochrome b-245 in steady-state kinetic experiments. Incubation of(More)
The membrane potential of cytoplasts, derived from human neutrophils, was depolarized by the activation of the superoxide-generating NADPH-dependent oxidase. The extent of the depolarization was inhibited by diphenylene iodonium and was therefore due directly to the activity of the oxidase, which must be electrogenic. The extent of the depolarization was(More)
Potassium channels play a key role in the regulation of membrane excitability. We investigated the gene expression response of the Kv4.2 subtype of potassium channel, in the rat hippocampus, to a brief (5 min) episode of kainic acid-induced seizures. Our results demonstrate that Kv4.2 expression is reduced in the granule cell layer of the dentate gyrus at 3(More)
The rat carotid body tissue reveals a photometrically measurable haem signal with absorbance maxima at 560 nm, 518 nm and 425 nm, suggesting the presence of a b-type cytochrome; this was confirmed by pyridine haemochrome and CO spectra. The quantity of cytochrome b was estimated to be 310 pmol.mg of protein-1. This haem is capable of H2O2 formation, which(More)
The contribution of voltage-dependent ion channels to nerve function depends upon their cell-surface distributions. Nevertheless, the mechanisms underlying channel localization are poorly understood. Two phenomena appear particularly important: the clustering of channels by membrane-associated guanylate kinases (MAGUKs), such as PSD-95, and the regional(More)
Low-level generation of reactive oxygen species (ROS) by endothelial cells in response to a variety of stimuli has been observed; however, the enzyme system responsible is unknown. Using a variety of techniques, we examined for components of the phagocyte superoxide-generating NADPH oxidase to elucidate whether this enzyme could be a source of(More)
The detergent sodium cholate was used to both solubilize and partially delipidate the nicotinic acetylcholine receptor from Torpedo californica. Using both native membranes and reconstituted membranes, it is shown that the detergent to lipid molar ratio is the most important parameter in determining the effect of the detergent on the functional properties(More)
In the nervous system the influx of Ca2+ orchestrates multiple biochemical and electrical events essential for development and function. A major route for Ca2+ entry is through voltage-dependent calcium channels (VDCCs). It is becoming increasingly clear that the precise contribution VDCCs make to neuronal function depends not only upon their specific(More)