Morien A, Wellman P J, Fojt J
Department of Psychology, Texas A&M University, College Station 778434235, USA.
Pharmacol Biochem Behav. 1995 Sep;52(1):169-74. doi: 10.1016/0091-3057(95)00084-a.
Extracellular levels of endogenous norepinephrine (NE) within rat paraventricular hypothalamus (PVN) vary across the diurnal cycle, with a peak in NE level noted at the onset of the dark cycle, at which time feeding occurs in a burst. The present experiment further examined the relationship between food intake and extracellular levels of NE within the PVN and within sites located outside of the hypothalamus. Adult male rats were implanted with concentric microdialysis probes aimed at either the PVN or brain sites outside the PVN. Measures of food intake and of extracellular NE were collected every hour over a 24-h period. Rats with PVN probes exhibited two peaks in extracellular NE. The first peak in PVN NE occurred within 1 h before the onset of the dark phase (ZT11) and was significantly correlated (p < 0.02) with a marked burst of feeding during the first hour of the dark phase. In addition, a second NE peak occurred 8 h into the dark phase (ZT19) but was not accompanied by feeding. Rats bearing non-PVN probes did not exhibit alterations in extracellular NE yet did show a pattern of feeding similar to that noted in the PVN rats. These data support the hypothesis that the burst of feeding evident at the onset of dark is related, in part, to an increase in PVN extracellular NE.(ABSTRACT TRUNCATED AT 250 WORDS)
大鼠室旁核（PVN）内源性去甲肾上腺素（NE）的细胞外水平在昼夜周期中有所变化，在黑暗周期开始时NE水平达到峰值，此时进食会突然增加。本实验进一步研究了PVN内以及下丘脑外部位的食物摄入量与NE细胞外水平之间的关系。成年雄性大鼠植入了针对PVN或PVN外脑区的同心微透析探针。在24小时内每小时收集食物摄入量和细胞外NE的测量数据。植入PVN探针的大鼠细胞外NE出现两个峰值。PVN中NE的第一个峰值出现在黑暗期开始前1小时（ZT11），并且与黑暗期第一小时显著的进食激增显著相关（p < 0.02）。此外，第二个NE峰值出现在黑暗期8小时（ZT19），但此时没有进食。植入非PVN探针的大鼠细胞外NE没有变化，但进食模式与植入PVN探针的大鼠相似。这些数据支持了这样的假设，即黑暗开始时明显的进食激增部分与PVN细胞外NE的增加有关。（摘要截断于250字）
