Efflux mechanisms situated in various brain barrier interfaces control drug entry into the adult brain; this review considers the effectiveness of these protective mechanisms in the embryo, fetus, and newborn brain. The longstanding belief that the blood-brain barrier is absent or immature in the fetus and newborn has led to many misleading statements with potential clinical implications. The immature brain is undoubtedly more vulnerable to damage by drugs and toxins; as is reviewed here, some developmentally regulated normal brain barrier mechanisms probably contribute to this vulnerability. We propose that the functional status of brain barrier efflux mechanisms should be investigated at different stages of brain development to provide a rational basis for the use of drugs in pregnancy and in newborns, especially in those prematurely born, where protection usually provided by the placenta is no longer present.

中文翻译：

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了解发育中的大脑屏障机制的最新进展：胎儿大脑中的妊娠，易感性或保护性药物和药物转运蛋白？

位于各种脑屏障接口中的外排机制控制药物进入成年大脑的进入。这篇综述考虑了这些保护机制在胚胎，胎儿和新生脑中的有效性。人们一直认为胎儿和新生儿不存在血脑屏障或血脑屏障不成熟，这导致了许多具有潜在临床意义的误导性陈述。毫无疑问，未成熟的大脑更容易受到药物和毒素的伤害。如本文所述，某些受发育调节的正常脑屏障机制可能是造成此漏洞的原因。我们建议应在大脑发育的不同阶段研究脑屏障外排机制的功能状态，以为在怀孕和新生儿（尤其是早产儿）中使用药物提供合理的基础，