“黑曼巴”是让人闻之色变的非洲毒蛇，它的毒液可在20分钟内夺去一个人的生命。但一项新研究显示，在这种蛇的致命毒液中藏有一种止痛效果堪比吗啡的物质，有望用于开发新型止痛药。
新一期英国期刊《自然》登载的报告说，法国研究人员在对“黑曼巴”的毒液进行分析后发现，其含有的一种由某类蛋白质组成的物质具有止痛效果。如果给实验鼠注射这种物质，它们的爪子和尾部承受热水灼烫的时间可以翻一倍，同时还可减轻与发炎相关的疼痛感。
据介绍，这类蛋白质的止痛效果可与常用的强力止痛药吗啡相媲美，但它却没有吗啡的某些副作用。比如注射吗啡可能导致实验鼠的呼吸频率降到危险程度，但注射这类蛋白质就不会出现这种现象。
研究人员说，实验鼠感受疼痛的机制与人相似，因此有望在上述发现的基础上开发新型止痛药。现在许多人对吗啡等止痛药产生了耐药性，但成功问世的新型止痛药却不多，这项研究成果是止痛药研发领域的一个好消息。
不过研究人员也有一个疑惑不解的问题，那就是“黑曼巴”作为毒蛇，为何需在自己的毒液中合成止痛物质。有研究者猜测这种物质可能会与毒液中的其他物质混合后发挥特殊作用，但还需进一步研究加以证实。（生物谷Bioon.com）
doi: 10.1038/nature11494
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Black mamba venom peptides target acid-sensing ion channels to abolish pain
Diochot S, Baron A, Salinas M, Douguet D, Scarzello S, Dabert-Gay AS, Debayle D, Friend V, Alloui A, Lazdunski M, Lingueglia E.
Polypeptide toxins have played a central part in understanding physiological and physiopathological functions of ion channels. In the field of pain, they led to important advances in basic research and even to clinical applications. Acid-sensing ion channels (ASICs) are generally considered principal players in the pain pathway, including in humans. A snake toxin activating peripheral ASICs in nociceptive neurons has been recently shown to evoke pain11. Here we show that a new class of three-finger peptides from another snake, the black mamba, is able to abolish pain through inhibition of ASICs expressed either in central or peripheral neurons. These peptides, which we call mambalgins, are not toxic in mice but show a potent analgesic effect upon central and peripheral injection that can be as strong as morphine. This effect is, however, resistant to naloxone, and mambalgins cause much less tolerance than morphine and no respiratory distress. Pharmacological inhibition by mambalgins combined with the use of knockdown and knockout animals indicates that blockade of heteromeric channels made of ASIC1a and ASIC2a subunits in central neurons and of ASIC1b-containing channels in nociceptors is involved in the analgesic effect of mambalgins. These findings identify new potential therapeutic targets for pain and introduce natural peptides that block them to produce a potent analgesia.
