But endorphins, it turns out, are too big to pass through the blood-brain barrier, a highly selective membrane that protects the brain from potentially harmful stuff in the

但事实证明， 内啡肽太大而无法通过血脑屏障，血脑屏障是一种高度选择性的膜， 可以保护大脑免受大脑中潜在有害物质的侵害。