title: Di-4-ANEPPS causes photodynamic damage to isolated cardiomyocytes.
abstract: Action potential recordings from isolated guinea pig ventricular cells in the whole-cell recording mode were used to study the toxic and photodynamic properties of the voltage-sensitive fluorescent dye di-4-ANEPPS. Staining of the cardiomyocytes with di-4-ANEPPS (30 or 60 microM; 10 min) did not alter the action potential shape. When the stained cells were illuminated (1W/cm2) severe effects on the action potential were observed. There was a prolongation of the action potential duration, occurrence of early afterdepolarizations, reduction of the membrane resting potential and eventually inexcitability. Addition of the antioxidant catalase (100 IU/ml) to the extracellular solution delayed the onset of these effects, suggesting that reactive-oxygen-intermediates take part in di-4-ANEPPS induced photodynamic damage. Since di-4-ANEPPS is a very important tool for optical membrane potential recordings in heart tissue and single cardiomyocytes catalase might be useful in suppressing photodynamic damage during optical potential recordings.
authors.affiliation: Institut für Medizinische Physik und Biophysik, Karl-Franzens-Universität Graz, Austria.
authors.forename: P
authors.initials: P
authors.lastname: Schaffer
authors.forename: H
authors.initials: H
authors.lastname: Ahammer
authors.forename: W
authors.initials: W
authors.lastname: Müller
authors.forename: B
authors.initials: B
authors.lastname: Koidl
authors.forename: H
authors.initials: H
authors.lastname: Windisch
mesh_terms: D000200:Action Potentials / Q000187:drug effects / Q000528:radiation effects; D000818:Animals; D002374:Catalase / Q000494:pharmacology; D004594:Electrophysiology; D006168:Guinea Pigs; D006321:Heart / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D006352:Heart Ventricles / Q000166:cytology / Q000187:drug effects / Q000528:radiation effects; D066298:In Vitro Techniques; D008027:Light; D008564:Membrane Potentials / Q000187:drug effects / Q000528:radiation effects; D009206:Myocardium / Q000166:cytology; D011726:Pyridinium Compounds / Q000633:toxicity*
chemical_list: D011726:Pyridinium Compounds; C050019:1-(3-sulfonatopropyl)-4-(beta)(2-(di-n-butylamino)-6-naphthylvinyl)pyridinium betaine; D002374:Catalase