Neurophysiology: Sensing temperature without ion channels
Mammals use cold-sensitive ion channels to translate information about the temperature of their surroundings into electrical signals that are taken up by thermoreceptor nerve cells. Here I investigate the thermoelectric properties of an extracellular gel removed from the electrosensors of sharks, and show that it develops significant voltages in response to tiny temperature gradients. This bulk property of the gel indicates that temperature can be translated into electrical information without the need for ion channels, a sensitivity that may help sharks to locate thermal fronts as feeding areas.