Dendritic organelles. (A) Hippocampal neuron stained for MAP2 (red), DAPI (blue), and the Golgi marker GM130 (green). Adapted from ; reproduced with permission from Elsevier, copyright 2005. (B) Three-dimensional reconstruction of serial electron micrographs showing the distribution of SER (dark gray) in dendrites and spines. Large flat compartments (arrowheads) are linked by thin extensions (thin arrows). Several spines are invaginated by SER (asterisks). Adapted from ; reprinted with permission from the Society for Neuroscience, copyright 2002 and deg; (C) Cultured hippocampal neurons expressing the mitochondrial targeting sequence of cytochrome oxidase fused to DsRed2. Dendritic mitochondria (red) are present in the dendritic shaft where they occasionally associate with dendritic spines (arrows). Adapted from ; reproduced with permission from Elsevier, copyright 2004. (D) Three-dimensional reconstruction of serial electron micrographs showing the distribution of dendritic endosomes in hippocampal neurons from adult rats (bottom) and rats at postnatal day 15 (top), postnatal day 21 (middle). Endocytic vesicles (yellow), endosomes (red), small vesicles (blue), and amorphous vesicles (black) are distributed throughout dendrites. Adapted from ; reprinted with permission from the Society for Neuroscience, copyright 2002; (E) Electron micrograph of the spine apparatus showing lamination of smooth ER (straight arrows) between regions of high electron density (wavy arrows). Adapted from ; reproduced with permission from the Society for Neuroscience, copyright 1997.