title: Computer-aided measurement of cell shortening and calcium transients in adult cardiac myocytes.
abstract: The contractile cycle of the cardiac myocyte is essentially controlled by the concentration of intracellular calcium ([Ca2+]i). Measurement of [Ca2+]i using Ca2+-dependent fluorescence and simultaneous monitoring of cell dynamics enable characterization of a variety of substances interacting with ion channels and contractile proteins. In this report we describe a novel method featuring up to 480 frames/s for monitoring rapid changes in cellular calcium and cell length, in which every individual cycle allows effective evaluation of major cell parameters. Computers aid in determination of time to peak (in ms), time to 50% decrease (ms), diastolic Ca2+ (relative fluorescence units, rfu), systolic Ca2+ (rfu), Ca2+ transients (rfu), DeltaCa2+/Delta(t) rise (rfu/s), and DeltaCa2+/Delta(t) fall (rfu/s). Contractile parameters are as follows: maximum cell length (microm), minimum cell length (microm), absolute cell shortening (microm), peak DeltaL/Delta(t) shortening (microm/s), and peak DeltaL/Delta(t) relaxation (microm/s). In summary, we succeeded in demonstrating that this system is a unique and valuable tool that allows simultaneous and accurate assessment of contractile parameters and of calcium movements of isolated adult cardiac myocytes.
authors.affiliation: Medizinische Klinik, Kardiologie, Charité der Humboldt-Universität Berlin, Germany.
authors.forename: P
authors.initials: P
authors.lastname: Bramlage
authors.forename: G
authors.initials: G
authors.lastname: Joss
authors.forename: A
authors.initials: A
authors.lastname: Staudt
authors.forename: A
authors.initials: A
authors.lastname: Jarrin
authors.forename: S
authors.initials: S
authors.lastname: Podlowski
authors.forename: G
authors.initials: G
authors.lastname: Baumann
authors.forename: K
authors.initials: K
authors.lastname: Stangl
authors.forename: S B
authors.initials: SB
authors.lastname: Felix
authors.forename: V
authors.initials: V
authors.lastname: Stangl
mesh_terms: D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology; D020013:Calcium Signaling / Q000502:physiology*; D002316:Cardiotonic Agents / Q000494:pharmacology; D048429:Cell Size / Q000187:drug effects / Q000502:physiology; D003285:Contractile Proteins / Q000502:physiology; D007091:Image Processing, Computer-Assisted; D007545:Isoproterenol / Q000494:pharmacology; D008856:Microscopy, Fluorescence; D018715:Microscopy, Video; D009206:Myocardium / Q000166:cytology*; D009568:Nitrendipine / Q000494:pharmacology; D051381:Rats
chemical_list: D002121:Calcium Channel Blockers; D002316:Cardiotonic Agents; D003285:Contractile Proteins; D009568:Nitrendipine; D007545:Isoproterenol