Brown adipose tissue (BAT) contributes to energy homeostasis via nonshivering thermogenesis. The BAT is densely innervated by the sympathetic nervous system (SNS) and activity of pre-autonomic neurons modulates the sympathetic outflow. Leptin, an adipocyte hormone, alters energy homeostasis and thermogenesis of BAT via several neuronal circuits; however, the cellular effects of leptin on interscapular BAT (iBAT)-related neurons in the hypothalamus remain to be determined. In this study, we used pseudorabies virus (PRV) to identify iBAT-related neurons in the paraventricular nucleus (PVN) of the hypothalamus and test the hypothesis that iBAT-related PVN neurons are modulated by leptin. Inoculation of iBAT with PRV in leptin receptor reporter mice (Lepr:EGFP) demonstrated that a population of iBAT-related PVN neurons expresses Lepr receptors. Our electrophysiological findings revealed that leptin application caused hyperpolarization in some of iBAT-related PVN neurons. Bath application of leptin also modulated excitatory and inhibitory neurotransmission to most of iBAT-related PVN neurons. Using channel rhodopsin assisted circuit mapping we found that GABAergic and glutamatergic Lepr-expressing neurons in the dorsomedial hypothalamus/dorsal hypothalamic area (dDMH/DHA) project to PVN neurons; however, connected iBAT-related PVN neurons receive exclusively inhibitory signals from Lepr-expressing dDMH/DHA neurons.

棕色脂肪组织（BAT）通过非颤抖产热作用促进能量稳态。BAT 受到交感神经系统 (SNS) 的密集支配，前自主神经元的活动调节交感神经的流出。瘦素是一种脂肪细胞激素，通过多个神经元回路改变 BAT 的能量稳态和生热作用；然而，瘦素对下丘脑肩胛间 BAT (iBAT) 相关神经元的细胞作用仍有待确定。在本研究中，我们使用伪狂犬病病毒（PRV）来鉴定下丘脑室旁核（PVN）中与 iBAT 相关的神经元，并检验 iBAT 相关 PVN 神经元受瘦素调节的假设。在瘦素受体报告小鼠 (Lepr:EGFP) 中用 PRV 接种 iBAT 表明，iBAT 相关的 PVN 神经元群体表达 Lepr 受体。我们的电生理学研究结果表明，瘦素的应用导致一些 iBAT 相关 PVN 神经元超极化。瘦素的沐浴应用还调节大多数 iBAT 相关 PVN 神经元的兴奋性和抑制性神经传递。使用通道视紫红质辅助电路映射，我们发现下丘脑背内侧/下丘脑背侧区域（dDMH/DHA）中表达 GABA 能和谷氨酸能 Lepr 的神经元投射到 PVN 神经元；然而，连接的 iBAT 相关 PVN 神经元仅接收来自表达 Lepr 的 dDMH/DHA 神经元的抑制信号。使用通道视紫红质辅助电路映射，我们发现下丘脑背内侧/下丘脑背侧区域（dDMH/DHA）中表达 GABA 能和谷氨酸能 Lepr 的神经元投射到 PVN 神经元；然而，连接的 iBAT 相关 PVN 神经元仅接收来自表达 Lepr 的 dDMH/DHA 神经元的抑制信号。使用通道视紫红质辅助电路映射，我们发现下丘脑背内侧/下丘脑背侧区域（dDMH/DHA）中表达 GABA 能和谷氨酸能 Lepr 的神经元投射到 PVN 神经元；然而，连接的 iBAT 相关 PVN 神经元仅接收来自表达 Lepr 的 dDMH/DHA 神经元的抑制信号。