Evaluating Antipruritics

Pruritus or itching is an unpleasant sensation that provokes a desire to scratch. Many factors such as chemical, mechanical, thermal and electrical stimuli can elicit the itch sensation.^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 proto-typical 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