ABSTRACT
Itching, or pruritus, is an unpleasant sensation that provokes a desire to scratch. Chemical, mechanical, thermal, and electrical stimuli can elicit itch (1-5). Mediators of itch, presumably, directly act on nerve fibers or lead to a nerve stimulation cascade whose final common pathway is interpreted in the central nervous system as itching (2-6). Putative receptors for itching are C-fibers with exceptionally low conduction velocities and insensitivity to mechanical stimuli (4-6). Histamine, the prototypical chemical mediator of itch, which is released during mast cell degranulation and mediates its effects in the skin via H1 receptor (3,5), is the best-known experimental pruritogen (2,3,5,7). Other pruritogens such as compound 48/80 (8,9), substance P (10,11), and serotonin (12) have been studied.
