Neurophysiological Studies of Schizophrenia

描述（由申请人提供）：本提交文件是RO1 MH040799的竞争性修订，以响应通知no - od -09-058 [NIH宣布竞争性修订申请的恢复法案资金可用性]。本修订版涉及以下NIMH感兴趣的领域-转化科学：开发精神障碍治疗的创新目标和模型。总体目标是创建一个体外动物高频（γ波段；约40Hz）新皮质振荡模型，使我们能够测试神经生物学模型，该模型是我们记录精神分裂症（Sz）患者γ波段异常发育过程的临床工作的基础（父母资助的具体目标1）。这种伽马带异常被认为是导致Sz执行功能缺陷的原因，目前很少有治疗方法来治疗这种疾病的这些方面。父母（临床）资助和当前竞争性修订的方法是基于我们的神经生物学模型：Sz的异常伽马带振荡是由涉及中间神经元上n -甲基- d -天冬氨酸（NMDA）受体的新皮质回路的发育调节改变引起的，导致皮质锥体神经元的复发性抑制缺陷。我们集中在一个新皮质区域，即前边缘皮层（PrL），这是人类背外侧前额叶皮层的小鼠同源物。该区域与Sz的执行功能缺陷有关，并已被确定为NIMH恢复法案基金的目标区域。临床尸检数据已经发现，精神分裂症患者大脑前额叶和其他区域的gaba能中间神经元异常，特别是负责复发抑制和含有钙结合小白蛋白（PV）的快速尖峰中间神经元。为了研究这些gabaergergy神经元在新皮质伽马带振荡中的作用，我们将使用GAD67启动子（GFP小鼠）控制下表达绿色荧光蛋白（GFP）的小鼠，允许在记录之前在线识别gabaergy神经元。全细胞记录将由pv阳性神经元进行，最初通过它们的快速尖峰行为进行识别，并通过事后标记进行确认。将使用拟精神氯胺酮或选择性NMDA受体亚型拮抗剂阻断NMDA受体，以验证我们关于NMDA（特别是NR2A）受体异常导致伽马异常的假设。在体外实验中，将使用药物（kainate, carbachol）在PrL脑切片中产生伽马波段振荡。将使用不同年龄的雄性或雌性小鼠[青春期前（14-24天），青春期（35-45天），成年（81-91天）]来测试(i)伽马振荡的功率和频率（ii）中间神经元上NMDA受体亚型和（iii）慢性氯胺酮的影响。我们相信，对参与产生新皮层伽马节律的细胞和分子因素的个体发生的更深入的了解将最终导致可以减轻Sz执行功能缺陷的治疗。

DESCRIPTION (provided by the applicant0: This submission is a competitive Revision of RO1 MH040799 in response to Notice NOT-OD-09-058 [NIH Announces the Availability of Recovery Act Funds for Competitive Revision Applications]. This revision addresses the following NIMH area of interest - Translational Science: Innovative Targets and Models for Developing Treatments for Mental Disorders. The overall goal is the creation of an in vitro animal model of high frequency (gamma band; approx 40Hz) neocortical oscillations allowing us to test the neurobiological model underlying our clinical work documenting the developmental timecourse of gamma band abnormalities in schizophrenia (Sz) patients (Specific aim 1 in the parent grant). Such gamma band abnormalities are thought to be responsible for executive function deficits in Sz and at present there are few therapeutic approaches to treat these aspects of the disease. The approach of the parent (clinical) grant and the current competitive revision is based on our neurobiological model: abnormal gamma band oscillations in Sz result from a developmentally regulated alteration in neocortical circuitry involving N-methyl-D-aspartate (NMDA) receptors on interneurons leading to defective recurrent inhibition of cortical pyramidal neurons. We focus here on one neocortical area, the prelimbic cortex (PrL), which is the murine homolog of the dorsolateral prefrontal cortex in humans. This area is implicated in executive function deficits in Sz and has been identified as a target area for NIMH Recovery Act funds. Clinical postmortem data have identified abnormalities in GABAergic interneurons in prefrontal and other areas in brains from schizophrenic patients, in particular fast-spiking interneurons responsible for recurrent inhibition and containing the calcium binding parvalbumin (PV). To study the role of these GABAergic neurons in neocortical gamma band oscillations we will use mice expressing green fluorescent protein (GFP) under the control of the GAD67 promoter (GFP mice), allowing on line identification of GABAergic neurons prior to recording. Whole-cell recordings will be made from PV-positive neurons identified initially by their fastspiking behavior and confirmed by post-hoc labeling. Blockade of NMDA receptors with the psychomimetic ketamine or selective NMDA receptor subtype antagonists will be used to test our hypothesis of an NMDA (specifically NR2A) receptor abnormality being responsible for gamma abnormalities. Pharmacological agents (kainate, carbachol) will be used to generate gamma band oscillations in PrL brain slices in vitro. Male or female mice at different ages [pre-pubertal (14-24 d), adolescent (35-45 d), adult (81-91 d)] will be used to test developmental and sex differences in (i) power and frequency of gamma oscillations (ii) subtype of NMDA receptors on interneurons and (iii) the effect of chronic ketamine. We believe a deeper understanding of the ontogenesis of the cellular and molecular elements involved in generating neocortical gamma rhythms will lead eventually to treatments which can alleviate executive function deficits in Sz. DESCRIPTION (provided by applicant): Schizophrenia is a major mental illnesses that causes its' victims and their families much anguish and is a major source of lost productivity and medical care expenses to our nation. The parent grant for this revision involves a longitudinal study of defective brain oscillations in the 40 Hz (gamma) range in schizophrenic patients. This competitive revision proposal is centered around the generation of an in vitro animal model allowing us to test our hypotheses of the neurons and neurotransmitter receptors responsible for the development of abnormal gamma oscillations in this disease.