title: Photoelectric recording of mechanical responses of cardiac myocytes.
abstract: A method to monitor contraction of isolated myocytes by transmicroscopic photometry is illustrated. Two photodiodes are mounted inside an inverse microscope used for visual control of a cell. Illumination of one diode varies in proportion to changes in cell length. The contraction signal is amplified in a comparator circuit. Spatial resolution of the device is in the order of 1 micron which corresponds to about 5% of cell shortening in the fully activated state of contraction. The method was tested on isolated myocytes from guinea-pig ventricle. Optical records of contraction in response to action potentials or during voltage clamp compare well with the contractile behavior of multicellular preparations.
mesh_terms: D000200:Action Potentials; D000818:Animals; D002118:Calcium / Q000502:physiology; D006168:Guinea Pigs; D006321:Heart / Q000502:physiology*; D009200:Myocardial Contraction; D009206:Myocardium / Q000166:cytology*
chemical_list: D002118:Calcium