Glutamate is a crucial neurotransmitter of the mammalian central nervous system, a molecular component of our diet, and a popular food-additive. However, for decades, concerns have been raised about the issue of glutamate’s safety as a food additive; especially, with regards to its ability (or otherwise) to cross the blood-brain barrier, cause excitotoxicity, or lead to neuron death. Results of animal studies following glutamate administration via different routes suggest that an array of effects can be observed. While some of the changes appear deleterious, some are not fully-understood, and the impact of others might even be beneficial. These observations suggest that with regards to the mammalian brain, exogenous glutamate might exert a double-sided effect, and in essence be a two-faced molecule whose effects may be dependent on several factors. This review draws from the research experiences of the authors and other researchers regarding the effects of exogenous glutamate on the brain of rodents. We also highlight the possible implications of such effects on the brain, in health and disease. Finally, we deduce that beyond the culinary effects of exogenous glutamate, there is the possibility of a beneficial role in the understanding and management of brain disorders.

谷氨酸盐是哺乳动物中枢神经系统的重要神经递质，是我们饮食中的分子成分，也是一种流行的食品添加剂。然而，几十年来，人们一直对谷氨酸作为食品添加剂的安全性问题感到担忧。特别是关于其（或其他）穿过血脑屏障，引起兴奋性毒性或导致神经元死亡的能力。通过不同途径施用谷氨酸后的动物研究结果表明，可以观察到多种作用。尽管其中一些更改看起来是有害的，但某些更改尚未完全理解，而其他更改的影响甚至可能是有益的。这些观察结果表明，对于哺乳动物的大脑而言，外源性谷氨酸可能发挥双面作用，并且本质上是一种双面分子，其作用可能取决于多种因素。这篇综述来自作者和其他研究人员关于外源谷氨酸对啮齿动物大脑影响的研究经验。我们还强调了这种作用对大脑，健康和疾病的可能影响。最后，我们推断出，除了外源性谷氨酸的烹饪作用之外，还有可能在理解和管理脑部疾病中发挥有益作用。