Intracellular gradients of free calcium visualized in sensory and neuronal cells by a high-performance fluorescence imaging system

This paper describes results obtained with a novel imaging system based on a fast CCD device. Sensor's output was digitized at 12 bit/pixel by customized electronics, reaching acquisition rates as high as 800 frames/s with a full-frame resolution of 128x128 pixels. The software developed for the project permitted the sequential capture of thousands of images directly to host PC RAM without frame loss even at the maximum readout rate (16 MHz). It is shown that the high spatio-temporal resolution of this apparatus is of value when investigating the time-course of rapid intracellular Ca2+ fluorescence transients, particularly those associated with neuronal action potentials near physiological temperature.