Module 10: Figure Itch signal transduction mechanisms
Itch transducing mechanisms.
The Itch circuitry seems to depend on two main pathways; the histamine-sensitive and the histamine-insensitive pathways. Pruritic stimuli such as histamine and 5-hydroxytryptamine act on receptors that stimulate phospholipase C3β (PLC3β) to open the TRPV1 channels. The histamine-insensitive pathway responds to other stimuli such as chloroquine, bovine adrenal medulla 8-22 peptide (BAM8-22) or thymic stromal lymphopoietin (TSLP) that act through different mechanisms to stimulate the opening of TRPA1 channels. The inward currents that flow through the TRPV1 and TRPA1 channels induce the generator potential that triggers the action potential that transfer information to the brain.