Neuronal plasticity affects correlation between the size of dendritic spine and its postsynaptic density

• Published in: Scientific reports Vol. 9; no. 1; p. 1693
• Main Authors: Borczyk, Malgorzata, Śliwińska, Małgorzata Alicja, Caly, Anna, Bernas, Tytus, Radwanska, Kasia
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 08-02-2019; Nature Publishing Group
• Subjects: 13/106; 14/28; 14/63; 631/378/1595/1554; 631/378/2597/2599; 631/378/548; 631/378/87; 64/60; Cores; Dendritic plasticity; Dendritic spines; Electron microscopy; Endoplasmic reticulum; Glutamic acid receptors (ionotropic); Hippocampus; Humanities and Social Sciences; Long-term potentiation; Microscopy; multidisciplinary; N-Methyl-D-aspartic acid receptors; Neural plasticity; Postsynaptic density; Science; Science (multidisciplinary); Spine; Stratum radiatum; Surface area; Synaptic plasticity; Synaptic strength
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-018-38412-7

Structural plasticity of dendritic spines is thought to underlie memory formation. Size of a dendritic spine is considered proportional to the size of its postsynaptic density (PSD), number of glutamate receptors and synaptic strength. However, whether this correlation is true for all dendritic spine volumes, and remains stable during synaptic plasticity, is largely unknown. In this study, we take advantage of 3D electron microscopy and reconstruct dendritic spines and cores of PSDs from the
stratum radiatum
of the area CA1 of organotypic hippocampal slices. We observe that approximately 1/3 of dendritic spines, in a range of medium sizes, fail to reach significant correlation between dendritic spine volume and PSD surface area or PSD-core volume. During NMDA receptor-dependent chemical long-term potentiation (NMDAR-cLTP) dendritic spines and their PSD not only grow, but also PSD area and PSD-core volume to spine volume ratio is increased, and the correlation between the sizes of these two is tightened. Further analysis specified that only spines that contain smooth endoplasmic reticulum (SER) grow during cLTP, while PSD-cores grow irrespectively of the presence of SER in the spine. Dendritic spines with SER also show higher correlation of the volumetric parameters than spines without SER, and this correlation is further increased during cLTP only in the spines that contain SER. Overall, we found that correlation between PSD surface area and spine volume is not consistent across all spine volumes, is modified and tightened during synaptic plasticity and regulated by SER.