Calcium-induced calcium release of CICR across the cell causes the significant increase in cytosolic Ca that is important in activating muscle contraction. Calcium-induced calcium release Calcium-induced calcium release (CICR) describes a biological process whereby calcium is able to activate calcium release from intracellular Ca stores (e.g., endoplasmic reticulum or sarcoplasmic reticulum). Although CICR was first proposed for skeletal muscle in the 1970s, it is now known that CICR is unlikely to be its primary mechanism for activating SR calcium release. Instead, CICR is thought to be crucial for excitation-contraction coupling in cardiac muscle and it is now obvious that CICR is a widely
Calcium imaging dye in all cells or selectively in certain cellular subtypes. GECIs have been used in the studies of neuron, T-cell, cardiomyocyte, etc. Regardless of the type of indicator used the imaging procedure is generally very similar. Isolated cells loaded with an indicator or expressing it in the case of GECI, can be viewed using a fluorescence microscope and captured by a Scientific CMOS (sCMOS) camera or CCD camera. Confocal and two-photon microscopes provide improved sectioning ability so that calcium signals can be resolved in micro domains or (for example) synaptic boutons. Images are analyzed by measuring fluorescence intensity changes for