Song C Kay, Schwartz Gary J, Bartness Timothy J
Dept. of Biology, Georgia State Univ., 24 Peachtree Center Ave. NE, Atlanta, GA 30302-4010, USA.
Am J Physiol Regul Integr Comp Physiol. 2009 Mar;296(3):R501-11. doi: 10.1152/ajpregu.90786.2008. Epub 2008 Dec 24.
The origins of the sympathetic nervous system (SNS) innervation of white adipose tissue (WAT) have been defined using the transneuronal viral retrograde tract tracer, pseudorabies virus. Activation of this SNS innervation is acknowledged as the principal initiator of WAT lipolysis. The central control of WAT lipolysis may require neural feedback to a brain-SNS-WAT circuit via WAT afferents. Indeed, conventional tract tracing studies have demonstrated that peripheral pseudounipolar dorsal root ganglion (DRG) sensory cells innervate WAT. The central nervous system projections of WAT afferents remain uncharted, however, and form the focus of the present study. We used the H129 strain of the herpes simplex virus-1 (HSV-1), an anterograde transneuronal viral tract tracer, to define the afferent circuits projecting from WAT to the central nervous system. Siberian hamster inguinal (IWAT) or epididymal WAT was injected with H129 and the neuraxis processed for HSV-1 immunoreactivity. We found substantial overlap in the pattern of WAT sensory afferent projections with multiple SNS outflow sites along the neuraxis, suggesting the possibility of WAT sensory-SNS circuits that could regulate WAT SNS drive and thereby lipolysis. Previously, we demonstrated that systemic 2-deoxy-d-glucose (2DG) elicited increases in the SNS drive to IWAT. Here, we show that systemic 2DG administration also significantly increases multiunit spike activity arising from decentralized IWAT afferents. Collectively, these data provide structural and functional support for the existence of a sensory WAT pathway to the brain, important in the negative feedback control of lipid mobilization.
利用跨神经元病毒逆行示踪剂伪狂犬病病毒，已明确了白色脂肪组织（WAT）的交感神经系统（SNS）神经支配的起源。这种SNS神经支配的激活被认为是WAT脂肪分解的主要启动因素。WAT脂肪分解的中枢控制可能需要通过WAT传入神经向脑 - SNS - WAT回路进行神经反馈。事实上，传统的示踪研究已证明外周假单极背根神经节（DRG）感觉细胞支配WAT。然而，WAT传入神经的中枢神经系统投射仍不清楚，这构成了本研究的重点。我们使用单纯疱疹病毒1型（HSV - 1）的H129株，一种顺行跨神经元病毒示踪剂，来确定从WAT投射到中枢神经系统的传入回路。将H129注射到西伯利亚仓鼠的腹股沟（IWAT）或附睾WAT中，并对神经轴进行HSV - 1免疫反应性处理。我们发现WAT感觉传入投射模式与沿神经轴的多个SNS流出部位有大量重叠，这表明存在WAT感觉 - SNS回路的可能性，该回路可调节WAT的SNS驱动，从而调节脂肪分解。此前，我们证明全身给予2 - 脱氧 - d - 葡萄糖（2DG）会引起SNS对IWAT驱动的增加。在这里，我们表明全身给予2DG也会显著增加来自分散的IWAT传入神经的多单位放电活动。总的来说，这些数据为存在一条通向大脑的WAT感觉通路提供了结构和功能支持，这在脂质动员的负反馈控制中很重要。
