The role of protein kinase Mzeta in hippocampal-dependent memory maintenance.

描述（由申请人提供）：拟议项目的广泛目标是了解长期记忆如何通过蛋白激酶Mzeta（PKM？）的活性储存在大脑中。使用大鼠，该项目将确定特定的子集，需要PKM？活动的维护，以更好地了解PKM？大脑中的需求。将讨论三个具体目标。第一个目的是确定是否PKM？在海马体和杏仁核中需要不同的活动来维持令人厌恶的、基于上下文的记忆。为了实现这一目标，微量恐惧条件反射（TFC）将被用来创建一个令人厌恶的基于上下文的记忆，需要海马体和杏仁核的收购（1，2）。在TFC中，中性条件刺激（CS）与厌恶性非条件刺激（US）配对，两个刺激之间有一个空的跟踪期。第二个目标，解决食欲空间记忆是否需要海马PKM？活动，将使用基于空间的8臂径向臂迷宫任务来实现。在径向臂迷宫任务中，大鼠必须使用空间线索来确定8个可用臂中的哪4个包含隐藏的蔗糖颗粒。该任务需要海马体用于获取，并且依赖于训练室中的外部空间线索，而不是设备（3）内存在的上下文线索。最终的目的是确定是否存在不同的要求海马PKM？活动在维持空间和上下文食欲记忆协会。为了实现这一目标，将使用位置条件反射任务来创建海马依赖性食欲背景记忆，该记忆可以直接与aim 2中使用的空间径向臂迷宫记忆进行比较。在位置条件反射中，蔗糖颗粒在一种情况下重复可用，而在第二种情况下不提供奖励，导致动物在随后的测试中更喜欢蔗糖配对的情况（40）。为了测试海马PKM的需求？活动在每一个这些形式的记忆，一个特定的，有效的抑制剂PKM？活动称？在每个记忆的存储阶段，将假底物抑制肽（ZIP）局部显微注射到背侧海马体或杏仁核中（5）。动物将准备双侧插管，对准适当的结构，以允许药物的限制性局部注射。 这组实验将阐明是否PKM？需要维持广泛的海马依赖性记忆，或者它是否只维持需要海马获取的记忆的独家子集。这项研究对改善人类患者的记忆储存和破坏适应不良的记忆储存都有重要意义。 公共卫生相关性：该项目将扩展目前关于长期记忆存储生理基础的文献。增强对记忆维持的生物学机制的理解不仅对增加我们对这一过程的基本知识是必要的，而且对将研究结果转化为人类正常和紊乱的记忆也是必要的。

DESCRIPTION (provided by applicant): The broad goal of the proposed project is to understand how long-term memories are stored in the brain through the activity of protein kinase Mzeta (PKM?). Using rats, this project will determine the specific subset of hippocampal-dependent associations that require PKM? activity for maintenance to better understand PKM? requirements in the brain. Three specific aims will be addressed. The first aim is to determine whether PKM? activity is differentially required in the hippocampus and amygdala to maintain aversive, contextually-based memories. To achieve this aim, trace fear conditioning (TFC) will be used to create an aversive context-based memory that requires both the hippocampus and amygdala for acquisition (1,2). In TFC, a neutral conditioned stimulus (CS) is paired with an aversive unconditioned stimulus (US) with an empty trace period separating the two stimuli. The second aim, which addresses whether appetitive spatial memory requires hippocampal PKM? activity, will be achieved using the spatially-based 8-arm radial arm maze task. In the radial arm maze task, rats must use spatial cues to determine which 4 of the 8 available arms contain hidden sucrose pellets. This task requires the hippocampus for acquisition and relies on external spatial cues in the training room, rather than contextual cues present within the apparatus (3). The final aim is to determine whether different requirements exist for hippocampal PKM? activity in the maintenance of spatial and contextual appetitive memory associations. To achieve this goal, the place conditioning task will be used to create a hippocampal- dependent appetitive context memory that can be directly compared with the spatial radial arm maze memory used in aim 2. In place conditioning, sucrose pellets are repeatedly available in one context while no reward is provided in a second context, leading the animal to prefer the sucrose-paired context in a subsequent test (40). In order to test the requirement for hippocampal PKM? activity in each of these forms of memory, a specific, potent inhibitor of PKM? activity called ?-pseudosubstrate inhibitory peptide (ZIP) will be locally microinjected into the dorsal hippocampus or amygdala during the storage phase of each memory (5). Animals will be prepared with bilateral cannulae aimed at the appropriate structure to allow for restricted, local injection of the drug. This set of experiments will elucidate whether PKM? is required to maintain a broad set of hippocampal- dependent memories or whether it only maintains an exclusive subset of memories that require the hippocampus for acquisition. This research has important implications for both improving memory storage and disrupting maladaptive memory storage in human patients. PUBLIC HEALTH RELEVANCE: This project will expand the current literature on the physiological underpinnings of long-term memory storage. Enhanced understanding of the biological mechanisms underlying memory maintenance is necessary not only to increase our basic knowledge of this process, but also to potentially translate research findings to both normal and disordered memory in humans.