Physiology: Why cold is such a pain
Katharina Zimmermann and colleagues show that a protein called Nav1.8 allows information to be transmitted along sensory nerve fibres in cold conditions. The molecule is a voltage-gated sodium channel, an integral membrane protein that allows sodium ions to pass through a neuron's outer membrane.
There are other voltage-gated sodium channels in sensory neurons, but this one keeps working when the temperature drops — in fact, its currents are actually larger in colder conditions. This may help explain why, although sensory acuity deteriorates at cold temperatures, pain perception persists and cold stimuli themselves can be painful.
CONTACTKatharina Zimmermann (University Erlangen-Nuremberg, Erlangen, Germany)
Tel: +49 91 31 85 22 228; E-mail: zimmermann@physiologie1.uni-erlangen.de