Secretin receptor-deficient mice exhibit robust food anticipatory activity
Secretin receptor-deficient mice exhibit robust food anticipatory activity
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DOI：
10.1016/j.neulet.2022.136462
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发表时间：
2022-01-29
影响因子：
2.5
通讯作者：
Nakamura, Takahiro J.
中科院分区：
文献类型：
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作者：
Sugiyama, Mizuki;Nishijima, Ichiko;Nakamura, Takahiro J.
在哺乳动物中，视交叉上核（SCN）是一个主要的昼夜节律起搏器，优化行为节律和生理事件的时间。正常情况下，昼夜行为节律是由环境光暗（LD）周期通过SCN夹带。然而，其他同步信号的每日节律，如食物供应，也出现了。当夜间啮齿类动物的食物供应仅限于一次重复的日餐时，它们在进食前几小时表现出增加的活动;这被称为食物预期活动（FAA）。许多研究表明，FAA是由具有昼夜节律特性的食物振荡器（FEO）介导的，而不是SCN。然而，FEO的神经位点和计时机制，包括其与胃肠激素信号的关系，仍然不清楚。在此，为了检查促胰液素受体信号传导是否是FEO所必需的，在促胰液素受体缺陷（Sctr（-/-））小鼠中研究了每日食物限制的影响。将成年野生型（WT）和Sctr（-/-）小鼠圈养在含有转轮的单独笼中，可随意进食，并处于LD循环（12小时：12小时）中至少2周。在适应条件后，逐渐限制食物获取时间，4小时限制性喂养持续10天以上。随后，小鼠自由进食2天，然后禁食2天。此后，在限制喂养和随后禁食期间，在WT和Sctr（-/-）小鼠中均观察到稳健的FAA。这些结果表明，促胰液素受体信号传导是不必要的计时机制的FEO。
In mammals, the suprachiasmatic nucleus (SCN) is a principal circadian pacemaker that optimizes the timing of behavioral rhythms and physiological events. Normally, circadian behavioral rhythms are entrained by the environmental light-dark (LD) cycle via the SCN. However, daily rhythms of other synchronizing signals, such as food availability, also emerge. When food availability is restricted to a single recurring daytime meal in nocturnal rodents, they exhibit increased activity during the hours immediately preceding feeding time; this is called food anticipatory activity (FAA). Many reports suggest that FAA is mediated by the food-entrainable oscillator (FEO) with circadian properties, but not the SCN. However, the neural locus and timekeeping mechanisms of the FEO, including its relationship with gastrointestinal hormone signaling, remain unclear. Herein, to examine whether secretin receptor signaling is necessary for the FEO, the effect of daily food restriction was studied in secretin receptor-deficient (Sctr(-/-)) mice. Adult wild-type (WT) and Sctr(-/-) mice were housed in separate cages containing a running wheel, with ad libitum food access and in a LD cycle (12 hours:12 hours) for at least 2 weeks. After acclimation to the condition, food access times were gradually restricted and 4-hour restricted feeding lasted over 10 days. Subsequently, mice had ad libitum food access for 2 days and then fasted for 2 days. Thereafter, robust FAAs were observed in both WT and Sctr(-/-) mice during restricted feeding and subsequent fasting. These results indicate that secretin receptor signaling is not essential for the timekeeping mechanism of FEO.