Medvedev, N. I.; Popov, V. I.; Dallérac, G.; Davies, H. A.; Laroche, S.; Kraev, I. V.; Roriguez Arellano, J. J.; Doyère, V. and Stewart, M. G.
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|DOI (Digital Object Identifier) Link:||http://dx.doi.org/doi:10.1016/j.neuroscience.2010.09.014|
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Alterations in curvature of the post synaptic density (PSD) and apposition zone (AZ), are believed to play an important role in determining synaptic efficacy. In the present study we have examined curvature of PSDs and AZs 24 h following homosynaptic long-term potentiation (LTP), and heterosynaptic long-term depression (LTD) in vivo, in awake adult rats. High frequency stimulation (HFS) applied to the medial perforant path to the dentate gyrus induced LTP while HFS stimulation of the lateral perforant path induced LTD in the middle molecular layer of the dentate gyrus (DG). Curvature changes were analysed in this area using three dimensional (3-D) reconstructions of electron microscope images of ultrathin serial sections. Very large and significant changes in 3-D measurements of AZ and PSD curvature occurred 24 h following both LTP and LTD, with a flattening of the normal concavity of mushroom spine heads and a change to convexity for thin spines. An N-methyl-d-aspartate (NMDA) receptor antagonist CPP (3-[(R)-2-Carboxypiperazin-4-yl]-propyl-1-phosphonic acid) blocked the changes in curvature of mushroom and thin spine PSDs and apposition zones, actually increasing the concavity of mushroom spines as the spine engulfed the presynaptic bouton. In order to establish whether these changes resulted from the effect of the NMDA antagonist or from its coincidence with synaptic activation during testing we examined the effects of CPP alone on PSD and apposition zone curvature. It was found that CPP alone also caused a small decrease in curvature of both PSD and apposition zone of mushroom and thin spines.
|Item Type:||Journal Article|
|Copyright Holders:||2010 IBRO Published by Elsevier Ltd.|
|Keywords:||3-D synaptic ultrastructure; hippocampus; long-term potentiation and depression|
|Academic Unit/Department:||Science > Life, Health and Chemical Sciences
|Interdisciplinary Research Centre:||Centre for Research in Computing (CRC)|
|Depositing User:||Astrid Peterkin|
|Date Deposited:||01 Nov 2010 10:51|
|Last Modified:||23 Nov 2012 19:42|
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