Gastric vagal afferents (GVAs) sense food related mechanical stimuli and signal to the central nervous system, to integrate control of meal termination. Pregnancy is characterized by increased maternal food intake, which is essential for normal fetal growth and to maximize progeny survival and health. However, it is unknown whether GVA function is altered during pregnancy to promote food intake. This study aimed to determine the mechanosensitivity of GVAs and food intake during early-, mid-, and late- stages of pregnancy in mice. Pregnant mice consumed more food compared to non-pregnant mice, notably in the light phase during mid- and late pregnancy. The increased food intake was predominantly due to light phase increases in meal size across all stages of pregnancy. The sensitivity of GVA tension receptors to gastric distension was significantly attenuated in mid- and late pregnancy, while the sensitivity of GVA mucosal receptors to mucosal stroking was unchanged during pregnancy. To determine whether pregnancy associated hormonal changes drive these adaptations, the effects of estradiol, progesterone, prolactin and growth hormone, on GVA tension receptor mechanosensitivity were determined in non-pregnant female mice. The sensitivity of GVA tension receptors to gastric distension was augmented by estradiol, attenuated by growth hormone and unaffected by progesterone or prolactin. Together, the data indicate that the sensitivity of GVA tension receptors to tension is reduced during pregnancy, which may attenuate the perception of gastric fullness and explain increased food intake. Further, these adaptations may be driven by increases in maternal circulating growth hormone levels during pregnancy.

中文翻译：

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小鼠胃迷走神经传入信号的妊娠相关可塑性

胃迷走神经传入（GVA）感知食物相关的机械刺激并向中枢神经系统发出信号，以整合对进餐的控制。怀孕的特征是增加了母亲的食物摄入量，这对于正常的胎儿生长以及最大限度地提高子代生存和健康至关重要。但是，尚不清楚怀孕期间GVA功能是否会改变以促进食物摄入。这项研究旨在确定小鼠妊娠早期，中期和晚期的GVA力学敏感性和食物摄入。与未怀孕的小鼠相比，怀孕的小鼠消耗的食物更多，特别是在怀孕中期和晚期处于轻度阶段。食物摄入量的增加主要是由于在怀孕的所有阶段，进食量的轻度阶段增加。GVA张力受体对胃扩张的敏感性在妊娠中期和晚期显着减弱，而GVA黏膜受体对粘膜抚摸的敏感性在妊娠期间未改变。为了确定妊娠相关的激素变化是否驱动这些适应，在未怀孕的雌性小鼠中确定了雌二醇，孕酮，催乳激素和生长激素对GVA张力受体机械敏感性的影响。雌二醇提高了GVA张力受体对胃扩张的敏感性，生长激素减弱了GVA张力受体的敏感性，而不受孕激素或催乳素的影响。总之，数据表明妊娠期间GVA张力受体对张力的敏感性降低，这可能会削弱对胃饱满感的认识并解释食物摄入的增加。进一步，