Two itch systems, one producing itchiness from histamines and the other not, both use TRPV1 receptors and use slowly conducting C fibers to send action potentials (as seen in heat-detecting neurons). However, TRP receptors for itching exclusively use the neurotransmitter natriuretic polypeptide B (Nppb) to stimulate neurons in the dorsal horn. Scratching the area of these receptors provides temporary relief by silencing these receptors with neuropeptide Y released from the spinal cord upon scratching.