Role of the Parasubthalamic Nucleus (PSTN) in Appetite Regulation

 描述(申请人提供)：禁食后两小时内出现饱腹感，并伴有大脑不同区域的神经元激活，包括下丘脑室旁核和背内侧核、臂旁核、孤束核的内侧和连合分支(NTS)、杏仁中央核(CEA)和终纹床核(BNST)，这些都通过影响大脑的自主神经和奖励中心而与调节食物摄入量有关。除了这些区域，我们在初步研究中观察到丘脑旁核(PSTN)中显著的CFOS激活，我们推测这是大脑中一个特征不佳的核，由饱腹感回路中的一个主要节点组成。为了验证这一假说，我们将使用经典的神经解剖学追踪技术(逆行和顺行)阐明再喂养激活的PSTN神经元是如何整合到中枢神经系统的，并测试这些神经元在调节食欲方面的功能，以及使用DREADDS来激活或抑制PSTN活性。将构建再摄食激活的PSTN神经元的投影路径的解剖图，包括PSTN中投射到已知食欲调节中心的神经元的地形图，以及激活的神经元是具有单一的专用投影场还是多个投影场。这一电路的功能将通过激活或抑制PSTN神经周膜的激活或抑制来测试，方法是使用表达DREADDS的AAV融合到双侧PSTN中的mCherry，其表达hM3Dq来激活PSTN神经元，或者表达hM4Di来沉默PSTN神经元，以响应氯氮平-N-氧化物(CNO)的全身给药。使用的行为读数将包括使用禁食-再喂养范例来测量自动笼子中的食物和水的摄入量以及运动活动，并通过操作条件反射来研究奖励喂养。我们认为，这些研究将导致对食欲如何被抑制的新见解，并更好地理解食物摄入量调节的潜在机制。

 DESCRIPTION (provided by applicant): Following fasting, satiety is observed within two hours after reintroducing food and accompanied by neuronal activation in distinct areas of the brain including the hypothalamic paraventricular nucleus and dorsomedial nucleus, parabrachial nucleus, medial and commissural subdivisions of the nucleus tractus solitarius (NTS), central nucleus of the amygdala (CeA) and bed nucleus of the stria terminalis (BNST) that have all been associated with the regulation of food intake by affecting autonomic and reward centers in the brain. In addition to these regions, we observed in our preliminary studies striking cfos activation in the parasubthalamic nucleus (PSTN), a poorly characterized nucleus in the brain that we hypothesize comprises a major node in the satiety circuitry. To test this hypothesis, we will elucidate how refeeding-activated PSTN neurons are integrated into the central nervous system using classic neuroanatomical tracing techniques (retrograde and anterograde), and to test the functionality of these neurons in the regulation of appetite, the use of DREADDs to activate or inhibit PSTN activity. Anatomical maps will be constructed of the projection pathways of refeeding-activated PSTN neurons including the topography of neurons in the PSTN that project to known appetite regulating centers and whether activated neurons have a single, dedicated projection field or multiple projection fields. The functionality of this circuitry will e tested by activating or inhibiting PSTN neuronal perikarya using AAV expressing DREADDs fused to mCherry injected bilaterally into the PSTN that either expresses hM3Dq to activate PSTN neurons or hM4Di to silence PSTN neurons in response to the systemic administration of clozapine-N-oxide (CNO). Behavioral readouts used will include measuring food and water intake and locomotor activity in automated cages using a fasting-refeeding paradigm, and by operant conditioning to study reward feeding. We propose that these studies will lead to new insights about how appetite is suppressed and better understanding about the mechanisms underlying the regulation of food intake.