The interoceptive cue properties of ghrelin generalize to cues produced by food deprivation
The interoceptive cue properties of ghrelin generalize to cues produced by food deprivation
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DOI：
10.1016/j.peptides.2005.02.014
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发表时间：
2005-09-01
期刊：
影响因子：
3
通讯作者：
Benoit, SC
中科院分区：
文献类型：
--
作者：
Davidson, TL;Kanoski, SE;Benoit, SC
最近的一些研究暗示肠脑肽胃饥饿素是一种假定的“饥饿信号”。然而，这些研究大多依赖于完成行为（在人类或非人类动物中）或自我报告（在人类中）来得出关于该肽的产氧特性的结论。本研究采用剥夺强度区分范式评估大鼠胃饥饿素的内感受性感觉特性。在这种模式下，一组大鼠被置于训练环境中，在24小时不进食时给予蔗糖颗粒，而在1小时不进食时（24+组）则没有。第二组采用相反的蔗糖剥夺水平偶然性（1+组）进行训练。在这种模式下，动物在有奖励的条件下比在无奖励的条件下更频繁地接近食物递送地点（在实际的颗粒递送之前）。在这些动物（被剥夺食物1小时）逐渐表现出这种辨别能力后，在训练环境中给予胃饥饿素或生理盐水，分别是1 / p（3或6 nmol）或1 / 3vt(0.1或1 nmol)，并测量食欲反应。测试是在消光状态下进行的，消除了食物消耗的混淆效应。实验结果表明，6 nmol i.p. ghrelin和0.1 nmol i3vt ghrelin和1 nmol i3vt ghrelin均普遍化到24 h食物剥夺状态，说明外源性ghrelin与24 h食物剥夺产生的刺激具有共同的感觉特性。这些结果支持了内源性胃饥饿素有助于内感受性饥饿提示的观点，这可能是胃饥饿素影响食物摄入和食欲行为的一种机制。(c) 2005爱思唯尔公司版权所有。
A number of recent studies implicate the gut-brain peptide ghrelin as a putative "hunger signal". Most of these studies, however, rely on either consummatory behavior (in humans or nonhuman animals) or self-report (in humans) to draw conclusions regarding the orexigenic properties of this peptide. The present study employs the deprivation intensity discrimination paradigm to assess the interoceptive sensory properties of ghrelin in rats. In this paradigm, one group of rats was placed in a training context and presented with sucrose pellets when 24 h food deprived, but not when 1 h food deprived (24+ group). A second group was trained using the opposite sucrose-deprivation level contingency (1+ group). Learning in this paradigm was demonstrated by animals approaching the food delivery location more frequently under their rewarded compared to their non-rewarded deprivation condition (prior to actual pellet delivery). After asymptotic performance of this discrimination was achieved, these animals (1 h food deprived) were administered ghrelin or saline, either i.p. (3 or 6 nmol) or i3vt (0.1 or 1 nmol), placed in the training context, and appetitive responses were measured. Testing was conducted in extinction, eliminating confounding effects of food consumption. Results of these tests showed that 6 nmol i.p. ghrelin and 0.1 and 1 nmol i3vt ghrelin all generalized to a state of 24 h food deprivation, indicating that exogenous ghrelin has sensory properties in common with the stimuli produced by 24 h food deprivation. These results support the notion that endogenous ghrelin contributes to an interoceptive hunger cue, and that this may be a mechanism by which ghrelin influences food intake and appetitive behavior. (c) 2005 Elsevier Inc. All rights reserved.