碩士 / 國立成功大學 / 藥理學研究所 / 104 / Social recognition reflects the ability to discriminate familiar from unfamiliar individuals and is critical for effective and appropriate social interaction and communication. In rodents, short-term social recognition memory (SRM) is mediated mainly by chemical cues (semiochemicals) perceived via the olfactory system, whereas the long-term SRM formation was found to be dependent on the hippocampus CA2 region. But the cellular and molecular mechanisms underlying CA2 regulation of SRM formation remain unclear. Given that oxytocin receptors (OXTR) are expressed in the hippocampus CA2 region, we aimed to determine whether oxytocin may regulate long-term synaptic plasticity in the hippocampal CA2 region and contribute the molecular mechanisms underlying CA2 regulation of SRM formation. Using an OXTR-reporter mouse in which the fluorescent protein Venus is expressed under the control of the OXTR gene promoter, we demonstrate that the OXTR is highly expressed in hippocampal CA2 pyramidal neurons. By using a conditional knockout mouse model, we found that genetic deletion of oxytocin receptors (OXTR-/-) from excitatory neurons leads to impaired performance in long-term SRM, while OXTR-/- mice showed normal innate preference for sociability and social novelty. In addition, we found that OXTR knocking out inhibits the induction of long-term potentiation (LTP) at the entorhinal synapses in the hippocampal CA2 region and decreased calcium/calmodulin-dependent protein kinase II (CamKII) phosphorylation in vitro after LTP induction. Application of oxytocin elicited a reversible enhancement of basal synaptic transmission in WT but not OXTR-/- mice. Furthermore, bilaterally stereotaxic injection of Cre-expressing adenovirus vectors in to the CA2 region of floxed OXTR mice developed significant impairment in the performance of long-term SRM, with preserved innate preference for sociability and social novelty. Taken together, these results support a novel role for hippocampal CA2 OXTR in the expression of long-term SRM.
| Identifer | oai:union.ndltd.org:TW/104NCKU5550008 |
| Date | January 2016 |
| Creators | Tsan-YuHsieh, 謝璨宇 |
| Contributors | Kuei-Sen Hsu, 許桂森 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 69 |
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