Omar M. E. Abdel-Salam
Editor

2014

Capsaicin, a homovanillic acid derivative (8-methyl-N-vanillyl-6-nonenamide), is the pungent ingredient in red peppers of the plant genus Capsicum, including chillies and jalapenos. Capsaicin has long been used as a probe for sensory neuronal mechanisms. This is because capsaicin selectively stimulates, and at large doses, defunctionalizes a subset of primary afferent neurons with unmyelinated C fiber or thinly myelinated Aδ fibers. Most capsaicin-sensitive fibers are polymodal nociceptors (which respond to a range of sensory stimuli including noxious heat, pressure, and chemical irritation) as well as heat nociceptors, mechano-heat insensitive chemonociceptors, and warm receptors.