Selective Inflammatory Pain Insensitivity In The African Naked Mole-Rat (Heterocephalus Glaber)

Main Category: Neurology / Neuroscience
Also Included In: Biology / Biochemistry
Article Date: 28 Jan 2008 - 17:00 PDT

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Chemicals such as capsaicin and acid are considered noxious because they cause irritation and pain when applied to the skin. Acid is, for example, a very noxious stimulus and can cause intense pain. Indeed acid is both noxious and painful to all animals including amphibians and fish. In a new paper published this week in the open-access journal PLoS Biology, Thomas Park, Gary Lewin, and colleagues describe for the first time a member of the rodent family, the African naked mole-rat (Heterocephalus glabor) that is behaviorally completely oblivious to capsaicin and acid. Tissue injury and inflammation increase sensitivity to normally non-painful stimuli, a phenomenon called hyperalgesia.

Here, they show that the naked mole-rat does not experience hyperalgesia to painful thermal stimuli after inflammation.

To their knowledge, no other mammal has so far been described that is selectively insensitive to chemical pain or that lacks thermal hyperalgesia. Naked mole-rats live in very large subterranean social groups and are remarkably tolerant to low oxygen and high carbon dioxide conditions. They hypothesize that naked mole rats are selectively pain insensitive partly because of selection pressure arising from the extremity of their normal habitat.

Selective inflammatory pain insensitivity in the African naked mole-rat (Heterocephalus glaber).
Park TJ, Lu Y, Ju¨ ttner R, Smith ESJ, Hu J, et al. (2008)
PLoS Biol 6(1):e13. doi:10.1371/journal.pbio.0060013
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