Itch-associated Neuropeptides and Their Receptor Expression in Dog Dorsal Root Ganglia and Spinal Cord
Joshua J. Wheeler, B. Duncan X. Lascelles, Thierry Olivry, Santosh K. Mishra
Preview of fully accepted paper, still not published in any volume
Most canine visits to veterinarians are related to skin diseases with itch being the chief complaint. Historically, several itch-inducing molecules and pathways have been identified in mice, but whether or not these are similar in dogs is not yet known. Herein, we set out to study the expression of pruritogenic neuropeptides, their cognate receptors with a limited functional validation thereof using a multidisciplinary approach. We demonstrated the expression of somatostatin and other major neuropeptides and receptors in canine dorsal root ganglia neurons. Next, we showed that interleukin-31, serotonin, and histamine activate such neurons. Furthermore, we demonstrated the physiological release of somatostatin from dog dorsal root ganglia neurons in response to several endogenous itch mediators. In summary, our results provide the first evidence that dogs use similar pruritogenic pathways to those characterized in mice and we thus identify multiple targets for the future treatment of itch in dogs.
In the last few years, molecular studies have characterized multiple itch mediators, receptors, and neurotransmitters/neuropeptides that are required for itch signaling in mice. However, it is unclear if similar signaling components and pathways are involved in the propagation of itch in dogs. Herein, we focus on the physiological expression and function of itch-associated receptors and neurotransmitters that were first implicated in generating the itch sensation in mice. Our work identifies several new potential targets for antipruritic therapies in dogs.