Dr. LaMotte's laboratory investigates the peripheral neural mechanisms of itch and pain.
The neural basis of itch is poorly understood despite its clinical importance. We are currently addressing the problem by means of NIH funded research to characterize peripheral neural mechanisms encoding acute and persistent itch. Our approach is to correlate psychophysical measurements of itch and pain in humans (measured in the LaMotte lab) with electrophysiological recordings from pruriceptive and nociceptive peripheral nerve fibers in the monkey (obtained in the laboratory of Matthias Ringkamp, Johns Hopkins School of Medicine) using the same types of pruritic and nociceptive stimuli. The correlations are used to identify candidate neural mechanisms that code the sensations of acute itch and pathologically persistent itch. For example, we are using novel pruritogens (pruritic chemicals) that selectively activate one or more types of cutaneous nociceptors to elicit itch. We also identify experimental conditions that can enhance the itch or the pain produced by these and other pruritogens, and we seek to define conditions where pain and itch coexist as can sometimes occur in clinical neuropathic or inflammatory diseases.
In preclinical models of inflammatory itch we are comparing the enhanced and persistent itch and pain accompanying either of two types of contact dermatitis - irritant dermatitis that activates the innate immune system and allergic contact dermatitis that additionally activates the adaptive immune system. We will determine the effects of reducing or eliminating activity in one set of nociceptive nerve fibers on the remaining sensibilities mediated by other types. Our approach will aid the development of anti-pruritic and analgesic therapies that selectively modify itch and pain.