Neurodevelopmental Effects of Moderate Prenatal Caffeine Exposure

描述(申请人提供)：怀孕期间经常摄入咖啡因。目前，建议孕妇将咖啡因的摄入量减少到每天300毫克以下。然而，由于咖啡因只会在极高剂量下导致胎儿畸形，因此低剂量接触这种药物还没有得到很好的研究。人们应该担心胎儿接触咖啡因，因为咖啡因跨越胎盘和血脑屏障，在胎儿大脑中积累。拟议的研究将调查低剂量(相当于每天2-3杯咖啡)产前长期接触咖啡因对胎儿神经发育的影响。第一组实验将确定在发育过程中，产前接触咖啡因是否会改变海马体中受体/通道的功能和/或数量。钙成像技术将被用来确定适度的产前咖啡因暴露是否改变海马神经元的钙调节。此外，还将使用Western印迹分析来确定钙瞬变是否由于表达的受体/通道数量的变化所致。这些研究很重要，因为咖啡因对腺苷受体的拮抗作用在许多离子通道和受体上都有间接作用。下一组实验将确定产前接触咖啡因是否会改变发育中的海马体细胞死亡和细胞数量。如果出生前接触咖啡因会由于受体/通道功能改变而加剧细胞死亡，那么海马体中的神经元可能会丢失。将进行TUNEL分析以测量不同时间点的细胞死亡水平，并将使用免疫组织化学方法估计咖啡因暴露组和对照组大鼠海马区神经元总数。最后，将对幼年大鼠进行学习和记忆的行为测量，以确定出生前接触咖啡因是否会产生长期的发育后果。这些研究与公众健康相关，因为咖啡因通常在怀孕期间消耗，怀孕期间使用咖啡因可能会对胎儿大脑发育和心理健康产生长期影响。大脑发育的这些变化可能表现为学习障碍，直到青春期或成年期才被诊断出来。因此，确定低剂量长期接触咖啡因是否对发育中的胎儿大脑有影响是极其重要和相关的。

DESCRIPTION (provided by applicant): Caffeine is commonly consumed during pregnancy. Currently, it is recommended that pregnant women reduce caffeine intake to less than 300 milligrams per day. Yet, because caffeine only causes malformations of the fetus at extremely high doses, low dose exposure to the drug has not been well studied. There should be concern over fetal exposure to caffeine because caffeine crosses both the placental and blood brain barriers to accumulate in the fetal brain. The proposed studies will investigate the effects of low dose (equivalent to 2-3 cups of coffee per day) chronic prenatal exposure to caffeine on fetal neurodevelopment. The first set of experiments will determine whether prenatal caffeine exposure alters the function and/or number of receptors/channels in the hippocampus during development. Calcium imaging techniques will be used to determine whether moderate prenatal caffeine exposure alters calcium regulation in hippocampal neurons. Also, Western blot analysis will be used to determine whether altered calcium transients are due to changes in the numbers of receptors/channels expressed. These studies are important because caffeine has indirect effects at many ion channels and receptors due to its anatagonism of adenosine receptors. The next set of experiments will determine whether prenatal caffeine exposure alters cell death and cell number in the developing hippocampus. If prenatal caffeine exposure enhances cell death due to altered receptor/channel function, there may be a loss of neurons in the hippocampus. TUNEL analysis will be performed to measure levels of cell death at various time points and immunohistochemistry will be used to estimate total neuron number in the hippocampus of caffeine exposed and control rats. Lastly, behavioral measures of learning and memory will be performed in juvenile rats to determine if there are long-lasting developmental consequences of prenatal caffeine exposure. These studies are relevant to public health because caffeine is commonly consumed during pregnancy and its use during pregnancy may have effects on fetal brain development and long-term effects on mental health. These changes in brain development may manifest as learning impairments that are not diagnosed until adolescence or adulthood. Thus, it is extremely important and relevant to determine whether low dose chronic exposure to caffeine has effects on the developing fetal brain.