Inhibitors phenylarsine oxides

Phenylarsine oxide (20 [rM 30 minutes) is used as an inhibitor for receptor-mediated (clathrin-mediated) endocytosis (48). 

Clathrin-mediated endocytosis can be blocked by several pharmacologic inhibitors, including the antipsychotic drug chlorpromazine (Thorazine), the natural product ikarugamycin, and the antiviral drug amantadine. The metabolic poisons phenylarsine oxide and sodium azide also block CMF but additionally inhibit protein synthesis. Culture of cells under conditions that deplete potassium or calcium, treatment of cells with hypertonic sucrose, or acidification of the cytoplasm by addition of... 

Phenylarsine oxide, an inhibitor of tyrosine phosphatase, caused a dose-dependent decrease in eNOS activity in total membrane and in purified eNOS fractions from porcine pulmonary artery endothelial cells, even though the latter had no detectable tyrosine phosphatase activity (Su and Block 2000). Phenylarsine oxide also caused a decrease in sulphydryl content and eNOS activity in purified bovine eNOS. The reduction in eNOS sulphydryl content and the inhibitory effect of phenylarsine oxide on eNOS activity were prevented by dithio-threitol, a disulphide-reducing agent. 

The observation that K+ currents recorded from NEB cells of OD mouse lung are insensitive to acute hypoxia (75) is at shght odds with data from H146 cells that suggest that human SCLC cells express a second, but conveiging, 02-sensing system (84). Thus, in the H-146 cell model maximal inhibitory concentrations of either of two structurally unrelated inhibitors of NADPH oxidase activity, diphenylene iodonium (DPI) and phenylarsine oxide (PAO), are unable to abolish completely the hypoxic depression of K+ currents (84). Whether the quantitative contributions of this oxidase versus an additional sensory pathway (which may be different in neonatal rabbit NEB cells and the human tumor cell model) are a result of species differences or cell type remains to be investigated. 

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