INRA, UMR914 Nutrition Physiology and Ingestive Behavior, F-75005 Paris, France.
Physiol Behav. 2011 Oct 24;104(5):675-83. doi: 10.1016/j.physbeh.2011.07.012. Epub 2011 Jul 21.
Acute mild stress induces an inhibition of food intake in rats. In most studies, the cumulative daily food intake is measured but this only provides a quantitative assessment of ingestive behavior. The present study was designed to analyze the reduction in food intake induced by acute stress and to understand which behavioral and central mechanisms are responsible for it. Two different stressors, restraint stress (RS) and forced swimming stress (FSS), were applied acutely to male Wistar rats. We first measured corticosterone and ACTH in plasma samples collected immediately after acute RS and FSS in order to validate our stress models. We measured food intake after RS and FSS and determined meal patterns and behavioral satiety sequences. The expressions of CRF, NPY and POMC in the hypothalamus were also determined immediately after acute RS and FSS. The rise in corticosterone and ACTH levels after both acute RS and FSS validated our models. Furthermore, we showed that acute stress induced a reduction in cumulative food intake which lasted the whole day for RS but only for the first hour after FSS. For both stressors, this stress-induced food intake inhibition was explained by a decrease in meal size and duration, but there was no difference in ingestion speed. The behavioral satiety sequence was preserved after RS and FSS but grooming was markedly increased, which thus competed with, and could reduce, other behaviors, including eating. Lastly, we showed that RS induced an increase in hypothalamic POMC expression. These results suggest that acute stress may affect ingestive behavior by increasing satiation and to some extent by enhancing grooming, and this may be due to stimulation of the hypothalamic POMC neurons.
急性轻度应激会抑制大鼠的摄食。在大多数研究中，累积的每日食物摄入量是测量的，但这只能提供摄食行为的定量评估。本研究旨在分析急性应激引起的食物摄入量减少，并了解哪些行为和中枢机制是导致这种减少的原因。两种不同的应激源，束缚应激（RS）和强迫游泳应激（FSS），被应用于雄性 Wistar 大鼠。我们首先测量了急性 RS 和 FSS 后立即从血浆样本中收集的皮质酮和 ACTH，以验证我们的应激模型。我们测量了 RS 和 FSS 后的食物摄入量，并确定了进食模式和行为饱食序列。CRF、NPY 和 POMC 在下丘脑的表达也在急性 RS 和 FSS 后立即确定。急性 RS 和 FSS 后皮质酮和 ACTH 水平的升高验证了我们的模型。此外，我们表明，急性应激会导致累积食物摄入量减少，这种减少持续一整天的 RS，但仅在 FSS 后的第一个小时内持续。对于这两种应激源，这种应激引起的食物摄入量抑制是由于每餐的大小和持续时间减少，但摄食速度没有差异。在 RS 和 FSS 后，行为饱食序列得到保留，但梳理行为明显增加，这与摄食等其他行为竞争，并可能减少这些行为。最后，我们表明 RS 诱导下丘脑 POMC 表达增加。这些结果表明，急性应激可能通过增加饱腹感来影响摄食行为，在某种程度上通过增强梳理行为来影响摄食行为，这可能是由于刺激下丘脑 POMC 神经元引起的。
