Activity-Dependent Exocytosis of Lysosomes Regulates the Structural Plasticity of Dendritic Spines.

Lysosomes have traditionally been viewed as degradative organelles, although a growing body of evidence suggests that they can function as Ca stores. Here we examined the function of these stores in hippocampal pyramidal neurons. We found that back-propagating action potentials (bpAPs) could elicit Ca release from lysosomes in the dendrites.

The lysosome or lysosome-related organelle may serve as a Ca2+ store in the boutons of hippocampal pyramidal cells.

Boutons are specialised presynaptic compartments that lie along the axons of central neurons. Release of neurotransmitter from boutons is tightly regulated by the level of intracellular calcium [Ca2+]i. A rise in Ca2+ level may be generated in several ways; entry of extracellular Ca2+ via voltage gated calcium channels (VGCCs), entry via ligand-operated channels (LOCs) or the release of Ca2+ from intracellular Ca2+ stores.