Spontaneous and experimentally evoked (Ca super(2+)) sub(i)-transients in cardiac myocytes measured by means of a fast Fura-2 technique

A setup for dual wavelength-excitation fluorescence measurements is introduced which permits a temporal resolution of up to 1 KHz, using the Ca super(2+)-sensitive fluorescent dye Fura-2. The system makes use of a novel technical solution for chopping between two excitation wavelengths which does not move any optical components. Two beams, which are alternatively opened or shut by a rotating chopper wheel, are united by a dichroic mirror and are used for low-noise epifluorescence microscopy. The system includes a device for fast changes of extracellular solution that can be used for studying various components of (Ca super(2+)) sub(i)-regulation in excitable and non-excitable cells. Sample recordings of spontaneous and experimentally-evoked (Ca super(2+)) sub(i)-transients from cardiac myocytes are presented.