New SPECT and PET Radiopharmaceuticals for Imaging Cardiovascular Disease

Figure 13

Apoptosis pathways. The intrinsic pathway (blue) in myocytes is mediated by mitochondria, initiated by release of cytochrome c (white spheres) into the cytosol or via extrinsic pathway (violet) through death receptors. Both processes result in caspase-3 activation that leads to a cleavage cascade that finally results in programmed cell death (PCD)   {red spheres represent different subclasses of caspases. IAP = inhibitor-of-apoptosis (green); family of proteins that bind and inhibit caspases}.