Like Marvel’s surly superhero Luke Cage, naked mole-rats are seemingly indestructible, nearly hairless creatures that are impervious to certain kinds of pain. This last power has puzzled researchers, because like other mammals, mole-rats have functional versions of a protein called TRPV1, which responds to painfully hot stimuli.
It turns out that a different protein, TrkA, is the key to the missing pain signals, Gary Lewin of the Max Delbrück Center for Molecular Medicine in Berlin and colleagues report in the Oct. 11 Cell Reports. Usually, TrkA detects inflammation and kicks off a molecular reaction that produces pain sensation by activating TRPV1. But naked mole-rats produce a version of TrkA that doesn’t trigger this pain cascade.
That means that certain nerve cells don’t become more sensitive after encountering something hot, such as capsaicin, a molecule that puts the burn in spicy peppers. Because naked mole-rats spend their time in hot African climates, the rodents might have evolved to not need the pain signals that come from heat, the authors speculate.