Fig. 3From: Role of GRPR in Acupuncture Intervention in the “Itch-scratch Vicious Cycle” Spinal Circuit of Chronic PruritusPrevious studies of itch pathway have focused on the spinal cord level. Peripheral pruritic mediators stimulate mast cells degranulation in the skin releasing histamine, and histamine-sensitive unmyelinated nerve endings conduct nerve impulses to the posterior horn of the spinal cord, through the spinal thalamic tract to the thalamus, feed backing to the somatosensory cortex pruritusBack to article page