Ion Channel Guides Blood-Seeking Bats

Vampire bats on the prowl decide where to sink their teeth into their prey with the help of a heat-sensitive ion channel protein located in nerves on their noses, suggests a report in Nature (DOI: 10.1038/nature10245). Collaborating with researchers in Venezuela, a team led by David Julius of the University of California, San Francisco, found a truncated version of the ion channel TRPV1 in the neurons located in the bat’s nose pits, which are features responsible for detecting thermal radiation. In most mammals, TRPV1, known for its activation by the hot-pepper compound capsaicin, triggers a nerve response to pain or temperatures greater than 43 °C. The modified ion channel isolated by Julius and coworkers, however, has a lower heat threshold—around 30 °C—which likely enables the bats to sensitively detect the warm veins of their prey. Using gene-sequencing techniques, the researchers determined that, compared with normal TRPV1, the bat’s modified ion channel is missing 62 amino acids from the carboxy terminus. Julius hopes that the information gleaned from this study will help his team further understand how changes to TRPV1 might lead to heat or pain hypersensitivity in humans.