演題詳細
Poster
薬物依存、乱用
Drug Addiction and Abuse
開催日 | 2014/9/12 |
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時間 | 11:00 - 12:00 |
会場 | Poster / Exhibition(Event Hall B) |
MHCクラス1のコカインの自己投与への関与
Involvement of Immune Protein MHC class I in The Development of Cocaine Self-Administration
- P2-345
- 村上 元 / Gen Murakami:1 Meng Hongrui / Hongrui Meng:2 枝村 光浩 / Mitsuhiro Edamura:2 古川 智範 / Tomonori Furukawa:3 福田 敦夫 / Atsuo Fukuda:3 岩下 寿秀 / Toshihide Iwashita:1 中原 大一郎 / Daiichiro Nakahara:4
- 1:浜松医科大学、再生感染病理学 / Dept. Regenerative and Infectious Pathology, Hamamatsu University School of Medicine 2:浜松医科大学・行動心理学 / Dept. Psychology, Hamamatsu University School of Medicine 3:浜松医科大学、神経生理学 / Dept. Neurophysiology, Hamamatsu University School of Medicine 4:浜松医科大学、メディカルフォトニクスセンター / Dept. Biofunctional Imaging Medical Photonics Research Center, Hamamatsu University School of Medicine
Cocaine addiction is a psychiatric disorder that remains a serious public health problem worldwide. Because effective pharmacological drugs have not been identified, further understanding of molecular mechanisms behind the development of cocaine addiction is important to find novel targets for the pharmacological treatment. In our previous study, we succeeded in ensuring daily 24-hr access to cocaine for mice by employing an intracranial drug delivery system with reverse microdialysis technique. Using this novel system, we screened for several knockout mice available at our university, and found that functional deficit of major histocompatibility complex class 1 (MHCI), a major player in the adaptive immune system, exaggerated cocaine-seeking behavior. It has been recently discovered that MHCI is expressed in the brain that has long been designated as an immune privilege region and plays an important role in the modulation of synaptic plasticity such as elimination of long-term depression and enhanced long-term potentiation, resulting in the enhanced synaptic connections. We sought to evaluate the possibility whether modulation of MHCI expression in the brain is involved in the process of persistent cocaine-seeking behavior of wild type mice. After subjecting wild-type mice to cocaine self-administration paradigm, we discovered that expression of MHCI was reduced only in the VTA, implying a possibility that MHCI expressed in the VTA is important in the development of cocaine self-administration. In consistent with this idea, cocaine-induced enhancement of synaptic inputs into dopaminergic neurons of the VTA was significantly larger in functional MHCI knockout mice than in wild-type mice. These results indicate that cocaine self-administration leads to reduction of MHCI expression and enhances inputs into dopaminergic neurons in the VTA, resulting in the development of cocaine self-administration.