A novel electrophysiological technique for locating cutaneous nociceptive and chemospecific receptors

Conventional electrophysiological techniques for locating a cutaneous nociceptive receptor involve squeezing of the skin in the distribution of the nerve. A novel technique for locating nociceptive and chemospecific receptors has been developed, based on the coupling of action potential activity that occurs between two unmyelinated fibers in the peripheral nerve. Application of a punctate cold probe to the skin increases the latency of the coupled action potential when it is placed on the receptive field of the cutaneous receptor. More than half of the receptors which were located using this technique did not respond to mechanical or heat stimuli and therefore would not have been found using the standard search technique. Preliminary evidence suggests that some of these non-mechano-heat-sensitive receptors may be chemospecific receptors.