In the labs of University of California, San Francisco and from the wilds of Venezuela scientists have discovered how vampire bats have evolved over the years with a unique weapon that enables them to zero in for a ravenous feed on the warmest blood vessels of their prey.
It's well known that bats can pinpoint their prey by emitting their chirps and squeaks like sonar as they fly to spot a tempting target meal by analyzing its returning echoes. However vampire bats do not fly, they run to any animal or unwary bird whose blood will satiate their hunger, and they are uniquely far more specialized than other bats, according the David Julius, a distinguished neurophysiologist at UCSF.
Julius and his lab colleagues found vampire bats or Desmodus rotundus – as they are scientifically known as - possess a unique heat-sensitive molecule within specialized nerve endings on the surface of their noses. This molecule detects infrared radiation signals from the heat of blood as it flows close beneath the skin of a prey's veins and arteries at about 86 degrees Fahrenheit.
Julius, and Elena O. Gracheva, a post-doctoral fellow in his lab, have been working to understand the genetic basis of the specialized nerves that are sensitive to heat in both humans and animals. They detected this molecule in varied pit vipers, including the western diamondback rattlesnake. He said, “But we didn't know where [else] to find them” until Julio F. Cordero-Morales, another post-doc in his lab, said he knew a research team in Venezuela whose members were studying the bats.
Promptly the Caracas group collected samples of nerve cell masses from the noses of wild vampire bats, shipped them to San Francisco in dry ice, and the Julius team went to work. The nerve cells they studied are similar to the molecules in human nerve fibers that give people acute sensitivity to the sensation of heat like that which comes from eating chilli peppers and spicy foods containing the heat-emitting chemicals called capsaicins. Analyzing the genes involved in heat sensitivity among animals like snakes and vampire bats is also leading Julius and his colleagues to study the possibility of new approaches to pain relief in humans, he said.
The nerves the researchers are studying in bats and snakes are akin to nerves in humans that cause such pain in nerve disorders like trigeminal neuralgia, a chronic pain condition that affects the trigeminal nerve, which carries sensation from face to brain. Julius is on the advisory board of a company called Hydra Biosciences, based in Cambridge, Mass., which seeks to develop novel drugs to treat pain, inflammation and other disorders based on the types of so-called “ion channel” nerve structures involved in the Julius lab's research. His lab's new discovery in vampire bats is published today in the journal Nature.
Pilates lowers blood pressure in hypertensive patients, study finds