When your stomach’s empty, it [--1--] the hormone ghrelin, to whet your appetite and get your juices flowing. But ghrelin doesn’t just make you [--2--]. It helps you track it down too—by sharpening your sense of smell. That’s according to a study out this week in the Journal of Neuroscience.

First, scientists injected rats with ghrelin, and videotaped their noses. Their sniffers ran on [--3--] for several hours following the injection. And the rats could detect fainter scents, too.

So then the researchers called in nine [--4--], to see if our sniffing powers get a boost from ghrelin. The volunteers took whiffs of various substances—like baby powder, tomatoes and rosemary chicken. And regardless of how appetizing each aroma was, the volunteers took deeper whiffs—even of plain air—after getting a shot of ghrelin.

All of which suggests we’ve [--5--] a number of tricks to avoid the ultimate game-over: starvation. Because knowing you’re famished is only half the battle. Actually tracking down that wooly mammoth? That’s what really counts.
【视听版科学小组荣誉出品】
pumps out crave a bite overdrive fasting humans evolved
"饥饿"让嗅觉更"给力" 当你饥肠辘辘时,胃就会分泌一种胃饥饿素来刺激你的食欲和津液. 不过, 胃饥饿素并不仅仅让你想吃一点点食物, 它还能帮你找到食物---让你的嗅觉更灵敏. 此研究成果出自本周《神经科学周刊》. [Jenny Tong 等人, 《胃饥饿素增强嗅觉灵敏度, 人类和啮齿动物的嗅觉研究》] 首先, 科学家在老鼠体内注射胃饥饿素并记录它们的鼻子活动. 它们的嗅探器在注射后的几小时内超常发挥, 居然能嗅出比平时更淡的味道. 于是, 研究人员找来9名斋戒人士, 看胃饥饿素是否能让我们的嗅觉能力得到提升. 志愿者们吸入一点点各种东西的味道,比如说爽身粉, 迷迭番茄鸡. 打一针激素后, 先不说这些香味多么诱人, 就算是清淡的空气, 志愿者们也能闻出些东西出来. 这些研究结果表明, 我们不断进化着各种技巧来避免被饿死的结局. 让你感觉到饥饿只是这种进化技巧一半, 让你找到食物才是这种技巧的关键所在.