title: Photoactivated inhibition of superoxide generation and protein kinase C activity in neutrophils by blepharismin, a protozoan photodynamically active pigment.
abstract: Blepharismin is an endogenous photosensitizing pigment found in the protozoan Blepharisma. This pigment inhibited the generation of superoxide anion (O2-.) in neutrophils not only via a diacylglycerol-induced protein kinase C (PKC)-dependent reaction but also by an arachidonate-induced PKC-independent reaction. The inhibition was light and concentration dependent for both reactions. Light-activated inhibition was strong at wavelengths between 520 and 570 nm but not above 610 nm. PKC activity in neutrophils and from rat brain was inhibited by blepharismin in a light- and concentration-dependent manner. Moreover, arachidonate-activated NADPH oxidase activity in a cell-free system was also inhibited by the pigment in a light- and concentration-dependent manner. These results suggest that blepharismin inhibits NADPH oxidase activation through the non-specific inhibition of various membrane-bound enzymes and that this inhibition may also be correlated with that of PKC.
authors.affiliation: Department of Medical Biology, Kochi Medical School, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Watanabe
authors.forename: K
authors.initials: K
authors.lastname: Edashige
authors.forename: H
authors.initials: H
authors.lastname: Kobuchi
authors.forename: Y
authors.initials: Y
authors.lastname: Kato
authors.forename: T
authors.initials: T
authors.lastname: Matsuoka
authors.forename: T
authors.initials: T
authors.lastname: Utsumi
authors.forename: T
authors.initials: T
authors.lastname: Yoshioka
authors.forename: A A
authors.initials: AA
authors.lastname: Horton
authors.forename: K
authors.initials: K
authors.lastname: Utsumi
mesh_terms: D000818:Animals; D002474:Cell-Free System; D056890:Eukaryota / Q000737:chemistry*; D008027:Light; D009247:NADH, NADPH Oxidoreductases / Q000037:antagonists & inhibitors; D019255:NADPH Oxidases; D009504:Neutrophils / Q000187:drug effects* / Q000378:metabolism; D010569:Perylene / Q000031:analogs & derivatives* / Q000302:isolation & purification / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D010777:Photochemistry; D010860:Pigments, Biological / Q000302:isolation & purification / Q000494:pharmacology*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors*; D013481:Superoxides / Q000378:metabolism*
chemical_list: D010860:Pigments, Biological; C092293:blepharismin; D013481:Superoxides; D010569:Perylene; D009247:NADH, NADPH Oxidoreductases; D019255:NADPH Oxidases; D011493:Protein Kinase C