title: Palytoxin-induced increase in cytosolic-free Ca(2+) in mouse spleen cells.
abstract: The effect of palytoxin (C(129)H(223)N(3)O(54)) on Ca(2+) homeostasis in immune cells has not been studied. Therefore, we investigated the effect of palytoxin on the cytosolic-free Ca(2+) concentration ([Ca(2+)](i)) in mouse spleen cells using a fluorescence Ca(2+) indicator, fura-2. Palytoxin (0.1-100 nM) increased [Ca(2+)](i) in a concentration-dependent manner. The palytoxin-induced increase in [Ca(2+)](i) was abolished by the omission of extracellular Ca(2+) or 1-[beta-[3-(4-methoxyphenyl)propoxy]-4-methoxyphenethyl]-1H-imidazole hydrochloride (SKF-96365, 100 microM), and was greatly inhibited by Ni(2+) (2 mM). Ouabain (0.5-1 mM) partially inhibited the palytoxin-induced response. There was no effect of decreased extracellular Na(+) (6.2 mM), tetrodotoxin (1 microM), verapamil (10 microM), nifedipine (10 microM), omega-agatoxin IVA (200 nM), omega-conotoxin GVIA (1 microM), omega-conotoxin MVIIC (500 nM), or La(3+) (100 microM). These results suggest that palytoxin increases [Ca(2+)](i) in mouse spleen cells by stimulating Ca(2+) entry through an SKF-96365-, Ni(2+)-sensitive pathway.
authors.affiliation: Department of Pathobiological Science, Obihiro University of Agriculture and Veterinary Medicine, Obihiro 080-8555, Japan. es@obihiro.ac.jp
authors.forename: Eiki
authors.initials: E
authors.lastname: Satoh
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Ishii
authors.forename: Masakazu
authors.initials: M
authors.lastname: Nishimura
mesh_terms: D000178:Acrylamides / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000378:metabolism* / Q000494:pharmacology; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002478:Cells, Cultured; D003064:Cnidarian Venoms; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D007093:Imidazoles / Q000494:pharmacology; D007811:Lanthanum / Q000494:pharmacology; D008297:Male; D051379:Mice; D009532:Nickel / Q000494:pharmacology; D009543:Nifedipine / Q000494:pharmacology; D010042:Ouabain / Q000494:pharmacology; D012964:Sodium / Q000494:pharmacology; D013154:Spleen / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D013779:Tetrodotoxin / Q000494:pharmacology; D014700:Verapamil / Q000494:pharmacology; D020867:omega-Agatoxin IVA / Q000494:pharmacology; D020866:omega-Conotoxin GVIA / Q000494:pharmacology; D020960:omega-Conotoxins / Q000494:pharmacology; D000095702:Polyether Toxins
chemical_list: D000178:Acrylamides; D002118:Calcium; D002121:Calcium Channel Blockers; D003064:Cnidarian Venoms; D007093:Imidazoles; D007811:Lanthanum; D009532:Nickel; D009543:Nifedipine; D010042:Ouabain; D012964:Sodium; D013779:Tetrodotoxin; D014700:Verapamil; D020867:omega-Agatoxin IVA; D020866:omega-Conotoxin GVIA; D020960:omega-Conotoxins; C075851:omega-conotoxin-MVIIC; C063159:1-(2-(3-(4-methoxyphenyl)propoxy)-4-methoxyphenylethyl)-1H-imidazole; C010272:palytoxin; D000095702:Polyether Toxins