发表在《科学》（Science）杂志上的一项研究表明，老鼠具有特殊的与痒有关而不是与疼痛有关的神经细胞。

    Scratching Surface of Itch

    A friend's four year old daughter recently complained to me about how badly her mosquito bite itched. She was about to burst into tears. The fact that an uncomfortable itchy sensation can drive many of us to distraction led many scientists to believe that the nervous system deals with itch much as it does pain. Others spent years looking, unsuccessfully, for neurons that tell us to scratch rather than that we just hurt.

    Now, according to a study in the August 7th issue of the journal Science, researchers say they've finally found specific itch neurons in mice. They located them in the mouse spinal cord by following up on previous research that showed that some mice respond to itchy stimuli more than others.

    When scientists knocked out the itch neurons, the mice no longer had the urge to scratch in response to known itchy stimulus. But they could still sense and avoid pain, showing that itch and pain are processed independently.The researchers hope that these findings could eventually lead to better treatments for chronic itch, by targeting the specific biochemical pathways involved. As for the four-year-old? She forgot about her itchy bug bite as soon as lunch arrived.

    破解发痒的秘密

    最近我的一个朋友的四岁大的女儿向我抱怨，她被蚊子叮咬后非常难受，以致于都快要哭出来了。鉴于瘙痒引起的不适能让我们中的大多数人心烦意乱，因此科学家 们相信神经系统在处理瘙痒的时候像处理疼痛一样。有些科学家们花了多年的时间想找到那些告诉我们挠痒的神经细胞而不是那些告诉我们疼痛的神经细胞，但是他 们没有获得成功。

    目前，根据发表在8月7日《科学》（Science）杂志上的一项研究，研究者们说他们终于在老鼠身上找到了特定的瘙痒神经细胞。以前的研究显示，相比于其它老鼠，有些老鼠对瘙痒刺激反应更甚，研究者们深入了这些研究，进而在老鼠的脊髓中找到了这些神经细胞。

    当科学家们把这些神经细胞从老鼠身上取走后，这些老鼠对已知的瘙痒刺激不再做出挠痒反应。但是，它们仍然能感受并避免疼痛，这表明老鼠的神经系统是分别处 理痒和疼痛的。研究者们希望，通过针对性地处理瘙痒过程中的特定生物化学途径，这些研究最终能帮助更好地治疗慢性瘙痒。对上面提到的那个四岁小女孩有何作 用呢？一到午餐时间到来，她就忘记蚊虫曾叮咬过她了。