Dysregulation of dopamine receptors in the basal ganglia in OCD and tic disorders: Positron Emission Tomography with [11C]-PHNO

摘要 行为和思维的无序重复模式是许多神经精神疾病的特征， 包括强迫症（OCD）和抽动秽语综合征（TS）和其它抽动障碍。 强迫症、强迫症和抽搐与皮质-基底神经节回路的失调有关， 对潜在的病理生理学细节仍然知之甚少。 有几条证据表明，多巴胺（DA）及其受体在TS和强迫症中的失调，但 目前尚不清楚，尤其是在强迫症中。我们最近在小鼠模型中的研究产生了新的见解， 与Hdc基因突变相关的TS和OCD的罕见遗传形式的病理生理学。平行 在这些小鼠（离体3 H雷氯必利结合）和少数成年Hdc携带者中进行的研究 TS突变（11 C-PHNOPET成像）显示黑质中D2/D3受体的上调， 以前的研究表明，D3上调可能代表对慢性DA过量的反应， 苍白球（GP）。在与强迫症无关的受试者中，11 C-PHNO PET成像显示了一种独特的模式： 与SN中D2/D3受体的结合增加，但在GP中不增加， 腹侧纹状体/腹侧核。我们推测，多巴胺信号的失调可能是由于 导致异常的奖励处理，我们最近在强迫症患者中描述了这一点。 这些试点数据不足以得出明确的结论;它们需要确认， 目前的建议旨在实现。DA受体重叠但不同模式的初步发现 两种相关神经精神疾病的异常为一项重要的比较研究奠定了基础。 我们将在60名成人受试者中进行11 C-PHNO PET成像：15名患有强迫症，15名患有TS/抽搐，15名患有两种强迫症 和抽搐（通常是共病），以及15名健康对照。这将使我们能够执行几个 分析，所有这些都牢牢地扎根于我们的试点数据。首先，我们将比较有抽搐和没有抽搐的个体;我们 我们希望在SN和GP中发现增加的D2/D3结合，这将扩展我们在 一种罕见的TS相关Hdc突变更普遍地发生在抽动患者身上，因此构成了一种罕见的真正的 从病理生理学的动物模型到人类的新见解。第二，我们将比较 有和没有强迫症的个体;我们预计腹侧纹状体的受体异常与 强迫症的发病率，而在GP结合将与抽搐合并症。最后，我们将使用 在整个数据集中连续的症状测量，表征D2/D3异常的模式， 跨越传统的诊断范畴。 这些研究将新的发现与最先进的方法结合在一起，以促进我们对 DA及其受体的失调如何导致行为和思维的无序重复模式 两种常见的神经精神疾病

ABSTRACT Disordered repetitive patterns of behavior and thought characterize numerous neuropsychiatric conditions, including obsessive-compulsive disorder (OCD) and Tourette syndrome (TS) and other tic disorders. Obsessions, compulsions, and tics are associated with dysregulation of the cortico-basal ganglia circuitry, but the underlying pathophysiological details remain poorly understood. Several lines of evidence implicate dysregulation of dopamine (DA) and its receptors in TS and OCD, but much remains unclear, especially in OCD. New insight has arisen from our recent studies in a mouse model of the pathophysiology of a rare genetic form of TS and OCD associated with a mutation in the Hdc gene. Parallel studies in these mice (ex vivo 3H raclopride binding) and in a small number of adult carriers of the Hdc mutation with TS (11C-PHNO PET imaging) revealed upregulation of D2/D3 receptors in the substantia nigra, where previous work suggests that D3 upregulation may represent a response to chronic DA excess, and in the globus pallidus (GP). In unrelated subjects with OCD, 11C-PHNO PET imaging revealed a distinct pattern: increased binding to D2/D3 receptors in the SN but not in the GP, and a previously uncharacterized increase in the ventral striatum/nucleus accumbens. We speculate that dysregulated DA signaling in the accumbens may contribute to abnormal reward processing, which we have recently characterized in individuals with OCD. These pilot data are not sufficient powered for definitive conclusions; they require confirmation, which the current proposal seeks to achieve. Our tentative finding of overlapping but distinct patterns of DA receptor abnormality in two related neuropsychiatric conditions sets the stage for an important comparative study. We will perform 11C-PHNO PET imaging in 60 adult subjects: 15 with OCD, 15 with TS/tics, 15 with both OCD and tics (which are frequently comorbid), and 15 healthy controls. This will permit us to perform several analyses, all firmly grounded in our pilot data. First, we will compare individuals with and without tics; we expect to find increased D2/D3 binding in the SN and GP, which would extend our findings in carriers of the rare TS-associated Hdc mutation to tic patients more generally and thus constitute a rare instance of true translation from an animal model of pathophysiology to new insight in humans. Second, we will compare individuals with and without OCD; we expect receptor abnormalities in the ventral striatum to be related to OCD symptomatology, while binding in the GP will be associated with tic comorbidity. Finally, we will use continuous symptom measures across the full dataset, characterizing patterns of D2/D3 abnormality that may cut across traditional diagnostic categories. These studies bring together new findings with state-of-the-art methodologies to advance our understanding of how dysregulation in DA and its receptors contributes to disordered repetitive patterns of behavior and thought in two common neuropsychiatric disorders.