title: Ca2+ enhancement of hemolysis induced by the topical anesthetic oxethazaine in vitro.
abstract: Oxethazaine (OXZ), a potent topical anesthetic, was found to induce red blood cell (RBC) lysis in vitro, depending upon concentrations of OXZ, RBC and Ca2+. In a 2% RBC suspension, 100 microM OXZ caused almost complete hemolysis in the presence of 1.3 mM Ca2+ with only a minimal effect in its absence, while higher concentrations of OXZ (400 microM<) produced hemolysis without Ca2+. The hemolysis induced by OXZ plus Ca2+ was preceded by a rapid increase in 45Ca2+ uptake by RBCs, with both the hemolysis and Ca2+ uptake being inhibited by 1 mM CoCl2, NiCl2, and quinine. Together with the Ca2+ influx, rapid influx of Na+ and efflux of K+ occurred, and an increasing external K+/Na+ concentration ratio inhibited both hemolysis and Ca2+ influx. Morphologically, OXZ plus Ca2+ caused rapid transformation to spheroechinocytes, the formation of blebs and the pinching-off of blebs, whereas OXZ alone produced membrane invagination. SDS-PAGE analysis of the ghosts prepared from the RBCs treated with OXZ plus Ca2+ revealed derangement of cytoskeletal components. OXZ is a rare drug that exhibits a Ca2+ ionophore-like action, increasing the Ca2+ permeability of plasma membranes.
authors.affiliation: Division of Toxicology, Niigata College of Pharmacy, Japan.
authors.forename: R
authors.initials: R
authors.lastname: Yasuno
authors.forename: T
authors.initials: T
authors.lastname: Oguma
authors.forename: Y
authors.initials: Y
authors.lastname: Masuda
mesh_terms: D000777:Anesthetics / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002463:Cell Membrane Permeability / Q000187:drug effects; D003470:Culture Media; D004591:Electrophoresis, Polyacrylamide Gel; D004910:Erythrocyte Membrane / Q000737:chemistry; D004912:Erythrocytes / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D004983:Ethanolamines / Q000494:pharmacology*; D006461:Hemolysis / Q000187:drug effects*; D066298:In Vitro Techniques; D017136:Ion Transport; D008297:Male; D008855:Microscopy, Electron, Scanning; D011188:Potassium / Q000378:metabolism; D011803:Quinine / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012964:Sodium / Q000378:metabolism
chemical_list: D000777:Anesthetics; D002121:Calcium Channel Blockers; D003470:Culture Media; D004983:Ethanolamines; D012964:Sodium; D011803:Quinine; C100289:oxethazaine; D011188:Potassium; D002118:Calcium