1. The calcium sensor synaptotagmin 1 is expressed and regulated in hippocampal postsynaptic spines
- Author
-
Suleman Hussain, Svend Davanger, Anne E. Anderson, Zita J. Dosa, Jakob B. Sørensen, Yi-Chen Lai, and Daniel Lawer Egbenya
- Subjects
Male ,0301 basic medicine ,Dendritic Spines ,Cognitive Neuroscience ,Presynaptic Terminals ,Down-Regulation ,Inhibitory postsynaptic potential ,Hippocampus ,Synaptotagmin 1 ,Rats, Sprague-Dawley ,03 medical and health sciences ,0302 clinical medicine ,Postsynaptic potential ,medicine ,Animals ,Active zone ,Rats, Wistar ,Cells, Cultured ,Mice, Knockout ,Kainic Acid ,Chemistry ,STX1A ,Cytoplasmic Vesicles ,Post-Synaptic Density ,Immunohistochemistry ,Disease Models, Animal ,Microscopy, Electron ,030104 developmental biology ,medicine.anatomical_structure ,Epilepsy, Temporal Lobe ,nervous system ,Schaffer collateral ,Synaptotagmin I ,Chronic Disease ,Excitatory postsynaptic potential ,Postsynaptic density ,Neuroscience ,030217 neurology & neurosurgery - Abstract
Synaptotagmin 1 is a presynaptic calcium sensor, regulating SNARE-mediated vesicle exocytosis of transmitter. Increasing evidence indicate roles of SNARE proteins in postsynaptic glutamate receptor trafficking. However, a possible postsynaptic expression of synaptotagmin 1 has not been demonstrated previously. Here, we used postembedding immunogold electron microscopy to determine the subsynaptic localization of synaptotagmin 1 in rat hippocampal CA1 Schaffer collateral synapses. We report for the first time that synaptotagmin 1 is present in rat hippocampal postsynaptic spines, both on cytoplasmic vesicles and at the postsynaptic density. We further investigated whether postsynaptic synaptotagmin 1 is regulated during synaptic plasticity. In a rat model of chronic temporal lobe epilepsy, we found that presynaptic and postsynaptic concentrations of the protein are reduced compared to control animals. This downregulation may possibly be an adaptive measure to decrease both presynaptic and postsynaptic calcium sensitivity in excitotoxic conditions.
- Published
- 2017