Opioid Modulation of Excitatory Synapses

描述(申请人提供)：毒瘾是一种神经和心理障碍，其特征是强迫性地摄入、渴望和寻求药物，并对吸毒者的生活产生负面影响。最近，成瘾被认为是一种学习和记忆的病理形式，它需要神经回路的长期变化。与这一建议一致，我们最近的研究表明，阿片类药物的长期治疗改变了培养的分离神经元中树突棘的稳定性。我科学生涯的最终目标是显著提高我们在系统和细胞水平上对药物成瘾的综合理解。我研究的科学目标是确定树突棘阿片类药物调节的细胞机制。本研究是由美国国家药物滥用研究所(NIDA)R01基金(DA020582)资助的，该基金包含三个具体目标：(1)进一步研究MORs在突触后调节树突棘中的作用及其内化。(2)鉴定和确定介导阿片类物质调节树突棘的Rho GTP酶。(3)鉴定和测定介导阿片类物质调节树突棘的蛋白激酶(S)。这个K02奖项将使我大大减少我的教学时间，这样我就可以把更多的精力投入到研究中(从占总努力的50%增加到75%)。我将以两种方式利用额外的25%的努力来加强和扩大R01项目：(1)通过新提出的实验，使用来自纹状体、腹侧被盖区(VTA)、额叶新皮质和海马体等大脑不同区域的脑片来增强特定的目标1和3：我们最近出人意料的结果表明，MORS可能存在于突触前或突触后的位置，具体取决于神经元的类型和大脑的区域。因此，为了更好地了解药物成瘾，我们将研究阿片类药物如何调节大脑不同区域的兴奋性突触传递。(2)学习和使用双光子显微镜技术研究慢性阿片类药物暴露过程中AMPA受体的转运：吗啡的慢性治疗降低了小型EPSCs的幅度，表明突触后AMPA受体被移除。这种方法的目的是为下一个未来的研究计划奠定坚实的基础，届时我资助的R01基金将进行竞争性续签。下一步的研究计划是阐明阿片类药物暴露期间AMPA受体运输的细胞机制。此外，这个K02奖项也将让我在阿片类药物药理学方面的培训上投入额外的努力。我将参加明尼苏达大学神经科学系和NIDA资助的药物滥用分子和细胞生物学基础中心的研讨会和会议。我将定期参加NIDA资助的冷泉港夏季课程，并参加神经科学和药理学的国内和国际科学会议。

DESCRIPTION (provided by applicant): Drug addiction is a neurological and psychological disorder characterized by compulsive intake, craving and seeking of drugs with negative impacts that adversely affect the lives of the drug abusers. Addiction has recently been proposed to be a pathological form of learning and memory, which requires long-term changes of neural circuits. Consistent with this proposal, our recent studies reveal that chronic treatment with opioids alters the stability of dendritic spines in cultured dissociated neurons. The ultimate goal of my scientific career is to significantly advance our integrated understanding of drug addiction at both system and cellular levels. The scientific objective of my research is to determine the cellular mechanism underlying opioid modulation of dendritic spines. My present research is funded by a National Institute on Drug Abuse (NIDA) R01 grant (DA020582) which contains three Specific Aims: (1) to further characterize the roles of MORs and their internalization in postsynaptic modulation of dendritic spines. (2) To identify and determine the Rho GTPase that mediates opioid modulation of dendritic spines. (3) To identify and determine the protein kinase(s) that mediate opioid modulation of dendritic spines. This K02 award will allow me to significantly reduce my teaching hours so that I can devote more of my effort to research (increased from 50% to 75% of total effort). I will use the extra 25% effort to strengthen and broaden the R01 project in two ways: (1) enhancing the Specific Aims 1 and 3 with newly proposed experiments using brain slices prepared from different regions of the brain including the striatum, ventral tegmental area (VTA), frontal neocortex and hippocampus: Our recent unexpected results reveal that MORs could exist in either pre or post-synaptic sites depending upon the types of neurons and the region of the brain. Therefore, to better understand drug addiction, we will investigate how opioids modulate excitatory synaptic transmissions in different regions of the brain. (2) Learning and using the two-photon microscopic technique to investigate AMPA receptor trafficking during chronic opioid exposure: Chronic treatment of morphine decreases the amplitude of miniature EPSCs, suggesting a removal of post-synaptic AMPA receptors. The objective of this approach is to lay a solid foundation for the next future research plan when my funded R01 grant is up for competitive renewal. This next future research plan is to clarify the cellular mechanism underlying the trafficking of AMPA receptors during opioid exposure. In addition, this K02 award will also allow me to devote extra effort to my training in opioid pharmacology. I will attend seminars and meetings in the Department of Neuroscience and the NIDA funded Basic Center for Molecular and Cellular Biology of Drug Abuse at the University of Minnesota. I will regularly attend the NIDA funded summer courses at Cold Spring Harbor and participate in national and international scientific meetings of neuroscience and pharmacology.