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 bers or lead to a nerve stimulation cascade whose nal common pathway is interpreted in the central nervous system as itching [2-6]. Putative receptors for itching are C-bers 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 reported. Recent studies of other pruritogens include cowhage spicules [13] and the bovine adrenal medulla 8-22 (BAM-22) peptide [14].
