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Due to copyright issues, an electronic copy of the thesis must be ordered from the faculty. For the faculty to have time to process the order, the order must be received by the faculty at the latest 2 days before the public defence. Orders received later than 2 days before the defence will not be processed. After the public defence, please address any inquiries regarding the thesis to the candidate.
Trial Lecture – time and place
See Trial Lecture.
Adjudication committee
- First opponent: Professor Andrew Bean, Rush University, Chicago, US
- Second opponent: Professor Clive R Bramham, UiB - University of Bergen, Norway
- Third member and chair of the evaluation committee: Researcher Maja Amedjkouh Puchades, University of Oslo, Norway
Chair of the Defence
Professor Reidar Tyssen, University of Oslo
Principal Supervisor
Professor Svend Davanger, University of Oslo
Summary
Synapses are anatomical and functional contact points between neurons. Their ability to change and adapt – synaptic plasticity – is believed to be an underlying mechanism for learning and memory.
The aims of this thesis were to expand our knowledge on a few proteins that play important roles in hippocampal synaptic transmission and plasticity. By using post-embedding immunogold electron microscopy complemented with other methods, this thesis provides some novel findings on the localization of three proteins – the IP3 receptor type 1 (IP3R1), SNAP-25, syntaxin-1 and Arc – at the ultrastructural level. These proteins play important roles in the regulation of synaptic signalling and plasticity and have several aspects related to calcium concentrations and calcium signalling.
One of the proteins of interest, the IP3 receptor type 1 (IP3R1), is an intracellular calcium channel. IP3R1 releases calcium from internal stores upon activation. Increasing intracellular calcium is an important event during synaptic signalling and plasticity. IP3R1 were found to be located at both presynaptic and postsynaptic compartments in hippocampal synapses, and also, interestingly, the levels of presynaptic IP3R1 increased in the early phase of hippocampal synaptic plasticity.
Moreover, the SNARE-proteins SNAP-25 and syntaxin-1, involved in presynaptic vesicle exocytosis, were characterized at both pre- and postsynaptic sites in hippocampal sites, including postsynaptic spines and possibly postsynaptic vesicles, for the first time demonstrated by quantitative immunogold electron microscopy.
New information about the presence of Arc, a protein that is also closely related to synaptic plasticity, were also presented, specifically locating it at presynaptic terminals as well as in extracellular vesicles of hippocampal synapses.
Overall, the thesis provides new findings on the synaptic localization of some important synaptic proteins, that are relevant for our understanding of synaptic plasticity.
Additional information
Contact the research support staff.