Glutamate-Induced Transient Modification of the Postsynaptic Density

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 98; no. 18; pp. 10428 - 10432
• Main Authors: Dosemeci, Ayse, Tao-Cheng, Jung-Hwa, Vinade, Lucia, Winters, Christine A., Pozzo-Miller, Lucas, Reese, Thomas S.
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 28.08.2001; National Acad Sciences; The National Academy of Sciences
• Subjects: Animals; Antibodies; Behavioral neuroscience; Biological Sciences; Biology; Calcium-Calmodulin-Dependent Protein Kinase Type 2; Calcium-Calmodulin-Dependent Protein Kinases - metabolism; Cell culture techniques; Cells, Cultured; Cultural groups; Density; Depolarization; Glutamic Acid - pharmacology; Hippocampus - cytology; Hippocampus - drug effects; Hippocampus - metabolism; Microscopy, Immunoelectron; Nerve Tissue Proteins - metabolism; Neurology; Neurons; Neurons - drug effects; Neurons - metabolism; Neurons - ultrastructure; Neuroscience; Postsynaptic density; Potassium - pharmacology; Rats; Rodents; Synapses
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.181336998

Depolarization of rat hippocampal neurons with a high concentration of external potassium induces a thickening of postsynaptic densities (PSDs) within 1.5-3 min. After high-potassium treatment, PSDs thicken 2.1-fold in cultured neurons and 1.4-fold in hippocampal slices compared with their respective controls. Thin-section immunoelectron microscopy of hippocampal cultures indicates that at least part of the observed thickening of PSDs can be accounted for by an accumulation of Ca2+/calmodulin-dependent protein kinase II (CaMKII) on their cytoplasmic faces. Indeed, PSD-associated gold label for CaMKII increases 5-fold after depolarization with potassium. The effects of high-potassium treatment on the composition and structure of the PSDs are mimicked by direct application of glutamate. In cultures, glutamate-induced thickening of PSDs and the accumulation of CaMKII on PSDs are reversed within 5 min of removal of glutamate and Ca2+from the extracellular medium. These results suggest that PSDs are dynamic structures whose thickness and composition are subject to rapid and transient changes during synaptic activity.