Opioid Modulation of Excitatory Synapses

描述（由申请人提供）：药物成瘾是一种神经和心理障碍，其特征是强迫性摄入、渴望和寻求药物，对药物滥用者的生活产生负面影响。最近有人提出，成瘾是一种学习和记忆的病理形式，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，长期使用阿片类药物治疗会改变培养的游离神经元树突棘的稳定性。我科学生涯的最终目标是在系统和细胞水平上显著推进我们对药物成瘾的综合理解。我研究的科学目标是确定阿片调节树突棘的细胞机制。我目前的研究是由国家药物滥用研究所（NIDA） R01拨款（DA020582）资助的，其中包含三个具体目标：(1)进一步表征MORs及其内化在树突棘突触后调节中的作用。(2)鉴定并确定介导树突棘阿片调节的Rho GTPase。(3)鉴定和确定介导树突棘阿片调节的蛋白激酶。这个K02奖将让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上（从50%增加到75%）。我将利用额外的25%的努力，以两种方式加强和扩大R01项目：(1)通过新提出的实验，利用从大脑不同区域（包括纹状体、腹侧被盖区（VTA）、额叶新皮层和海马体）制备的大脑切片，增强具体目标1和3：我们最近的意外结果表明，MORs可能存在于突触前或突触后，这取决于神经元的类型和大脑的区域。因此，为了更好地理解药物成瘾，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)学习并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：慢性吗啡治疗降低了微型EPSCs的振幅，表明突触后AMPA受体的去除。这种方法的目的是为我的下一个未来的研究计划奠定坚实的基础，当我资助的R01资助进行竞争性更新时。下一步的研究计划是阐明阿片类药物暴露过程中AMPA受体运输的细胞机制。此外，这个K02奖也可以让我在阿片类药物药理学方面投入更多的精力。我将参加神经科学系和NIDA资助的明尼苏达大学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资助的冷泉港暑期课程，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.