Bing C, Frankish H, Wang Q, Hopkins D, Keith J, Trayhurn P, Williams G
Department of Medicine, University of Liverpool, United Kingdom.
Am J Physiol. 1996 Jan;270(1 Pt 2):R111-7. doi: 10.1152/ajpregu.1996.270.1.R111.
Neuropeptide Y (NPY) is increasingly considered to be involved in the central regulation of energy balance. Our previous studies suggest that hypothalamic NPY neurons of the arcuatoparaventricular (ARC-PVN) projection are inhibited in association with the marked increases in brown adipose tissue (BAT) thermogenesis and uncoupling protein (UCP) gene expression in rats exposed to cold. We therefore hypothesized that the NPYergic ARC-PVN system would be activated in a thermoneutral environment, when energy expenditure falls to a minimum, and that this activation could mediate the fall in BAT activity. We measured regional hypothalamic NPY concentrations, hypothalamic NPY receptor binding, and NPY mRNA together with UCP mRNA levels in rats exposed to thermoneutrality (29 degrees C) for 24 h. At thermoneutrality, UCP mRNA levels fell to 42% of those in controls maintained at 22 degrees C, but there were no significant changes in hypothalamic NPY or NPY mRNA levels or in NPY receptor binding. We conclude that the fall in UCP mRNA expression occurring under short-term thermoneutral condition is mediated by neuroendocrine mechanisms other than increased activity of hypothalamic NPY neurons.
神经肽Y（NPY）越来越被认为参与能量平衡的中枢调节。我们之前的研究表明，在暴露于寒冷环境的大鼠中，弓状核-室旁核（ARC-PVN）投射的下丘脑NPY神经元受到抑制，同时棕色脂肪组织（BAT）产热和解偶联蛋白（UCP）基因表达显著增加。因此，我们推测，在热中性环境中，当能量消耗降至最低时，NPY能ARC-PVN系统会被激活，且这种激活可能介导BAT活性的下降。我们测量了暴露于热中性环境（29℃）24小时的大鼠下丘脑各区域的NPY浓度、下丘脑NPY受体结合情况、NPY mRNA以及UCP mRNA水平。在热中性环境下，UCP mRNA水平降至维持在22℃的对照组的42%，但下丘脑NPY或NPY mRNA水平以及NPY受体结合情况均无显著变化。我们得出结论，短期热中性条件下UCP mRNA表达的下降是由下丘脑NPY神经元活性增加以外的神经内分泌机制介导的。
