Division of Metabolism, Endocrinology, and Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan 48109, USA.
J Neurosci. 2010 Apr 21;30(16):5713-23. doi: 10.1523/JNEUROSCI.1001-10.2010.
Leptin acts via its receptor (LepRb) to regulate neural circuits in concert with body energy stores. In addition to acting on a number of hypothalamic structures, leptin modulates the mesolimbic dopamine (DA) system. To determine the sites at which LepRb neurons might directly influence the mesolimbic DA system, we examined the distribution of LepRb neurons and their projections within mesolimbic brain regions. Although the ventral tegmental area (VTA) contains DA LepRb neurons, LepRb neurons are absent from the amygdala and striatum. Also, LepRb-EGFPf mice (which label projections from LepRb neurons throughout the brain) reveal that few LepRb neurons project to the nucleus accumbens (NAc). In contrast, the central amygdala (CeA) and its rostral extension receive copious projections from LepRb neurons. Indeed, LepRb-specific anterograde tracing demonstrates (and retrograde tracing confirms) that VTA LepRb neurons project to the extended CeA (extCeA) but not the NAc. Consistently, leptin promotes cAMP response element-binding protein phosphorylation in the extCeA, but not NAc, of leptin-deficient animals. Furthermore, transgenic mice expressing the trans-synaptic tracer wheat germ agglutinin in LepRb neurons reveal the innervation of CeA cocaine- and amphetamine-regulated transcript (CART) neurons by LepRb neurons, and leptin suppresses the increased CeA CART expression of leptin-deficient animals. Thus, LepRb VTA neurons represent a subclass of VTA DA neurons that specifically innervates and controls the extCeA; we hypothesize that these neurons primarily modulate CeA-directed behaviors.
瘦素通过其受体(LepRb)与身体能量储存一起调节神经回路。除了作用于许多下丘脑结构外,瘦素还调节中脑边缘多巴胺(DA)系统。为了确定 LepRb 神经元可能直接影响中脑边缘 DA 系统的部位,我们检查了 LepRb 神经元及其在中脑边缘脑区中的投射的分布。尽管腹侧被盖区(VTA)含有 DA LepRb 神经元,但杏仁核和纹状体中没有 LepRb 神经元。此外,LepRb-EGFPf 小鼠(可标记整个大脑中 LepRb 神经元的投射)表明,很少有 LepRb 神经元投射到伏隔核(NAc)。相比之下,中杏仁核(CeA)及其延伸的头部接收来自 LepRb 神经元的丰富投射。事实上,LepRb 特异性顺行示踪表明(并且逆行示踪证实)VTA LepRb 神经元投射到扩展的 CeA(extCeA)而不是 NAc。一致地,瘦素促进瘦素缺乏动物的 extCeA 而不是 NAc 中的 cAMP 反应元件结合蛋白磷酸化。此外,在 LepRb 神经元中表达跨突触示踪剂麦胚凝集素的转基因小鼠揭示了 LepRb 神经元对 CeA 可卡因和安非他命调节转录物(CART)神经元的支配,并且瘦素抑制瘦素缺乏动物的 CeA CART 表达增加。因此,LepRb VTA 神经元代表特定支配和控制 extCeA 的 VTA DA 神经元的一个亚类;我们假设这些神经元主要调节 CeA 导向的行为。