Early weaning is associated with disruption of eating behavior. However, little is known about the mechanisms behind it. 5HT and DA systems are key regulators of homeostatic and hedonic eating behaviors, respectively. Thus, this study aims to evaluate the effects of early weaning on feeding behavior and 5HT and DA systems. For this, rats were submitted to regular (PND30) or early weaning (PND15) and between PND250 and PND300 were evaluated food intake of standard diet in response to 4 h food deprivation, during the 24 h period and per phase of the circadian cycle, in addition to the palatable food intake. Additionally, body mass and mRNA expression of 5HT1B, 5HT2C, SERT, DRD1 and DRD2 were evaluated in the hypothalamus and brainstem. The results demonstrate that early weaning promoted an increase in standard food intake in response to a 4 h food deprivation in the 24 h period and in the dark phase of the circadian cycle, in addition to an increased palatable food intake. No differences in body mass between regular or early weaning were observed. In the hypothalamus, increased mRNA expression of SERT and DRD1 was observed, but decreased 5HT1B mRNA expression. In the brainstem, the expression of 5HT1B, SERT, 5HT2C, DRD1 and DRD2 was increased in early weaned rats. In a nutshell, the stress promoted by early weaning has programmed the animals to be hyperphagic and to increase their palatable food intake, which was associated with modulation of 5HT and DA systems.

中文翻译：

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早期断奶会导致体内成年大鼠体内稳态和享乐性饮食行为受到干扰，并调节5-羟色胺（5HT）和多巴胺（DA）系统。

早期断奶与进食行为中断有关。但是，对其背后的机制知之甚少。5HT和DA系统分别是稳态和享乐饮食行为的关键调节器。因此，本研究旨在评估早期断奶对饲喂行为以及5HT和DA系统的影响。为此，将大鼠进行常规（PND30）或早期断奶（PND15），并在24小时周期内和昼夜节律周期的每个阶段中，对PND250和PND300之间的食物摄取4小时的食物进行评估，以评估标准饮食的食物摄入量，除了可口的食物摄入。此外，在下丘脑和脑干中评估了5HT1B，5HT2C，SERT，DRD1和DRD2的体重和mRNA表达。结果表明，除了增加可口的食物摄入量外，在24小时周期和昼夜节律的黑暗阶段，早期断奶还可以促进标准食物摄入量的增加（4小时）。在常规或早期断奶之间未观察到体重差异。在下丘脑中，SERT和DRD1的mRNA表达增加，但5HT1B mRNA的表达降低。在早期断奶的大鼠脑干中5HT1B，SERT，5HT2C，DRD1和DRD2的表达增加。简而言之，由于早期断奶所引起的压力使动物编程为摄食过多，并增加了可口的食物摄入，这与5HT和DA系统的调节有关。除了增加可口的食物摄入量。在常规或早期断奶之间未观察到体重差异。在下丘脑中，SERT和DRD1的mRNA表达增加，但5HT1B mRNA的表达降低。在早期断奶的大鼠脑干中5HT1B，SERT，5HT2C，DRD1和DRD2的表达增加。简而言之，由于早期断奶所引起的压力使动物编程为摄食过多，并增加了可口的食物摄入，这与5HT和DA系统的调节有关。除了增加可口的食物摄入量。在常规或早期断奶之间未观察到体重差异。在下丘脑中，SERT和DRD1的mRNA表达增加，但5HT1B mRNA的表达降低。在早期断奶的大鼠脑干中5HT1B，SERT，5HT2C，DRD1和DRD2的表达增加。简而言之，由于早期断奶所引起的压力使动物编程为摄食过多，并增加了可口的食物摄入，这与5HT和DA系统的调节有关。