Itch-associated responses of afferent nerve innervating the murine skin: Different effects of histamine and serotonin in ICR and ddY mice

To assess the itch-associated response of primary afferents innervating the murine skin in vivo, dose-response curves and time-courses for itch-scratc hing and cutaneous nerve firing responses to intradermal injections of prur itogens (histamine and serotonin) were compared in ICR and ddY mice. Seroto nin increased the itch-scratch response and cutaneous nerve firing in eithe r ICR or ddY mice. Histamine increased these two responses in ICR, but not ddY, mice. The dose-response curves and time-courses for serotonin- and his tamine-induced nerve firing were similar to those for the itch-scratch resp onse. The results suggest that cutaneous nerve firing evoked by peripherall y given pruritogens includes the itch-associated response.