GRPR and Pruritus: Notably, i.d. chloroquine or compound 48/80‐induced firing of spinal GRPR+ neurons was attenuated by a combination of GRPR and AMPAR antagonists,15 but not by GRPR antagonist alone, supported by behavioral experiments, indicating that the glutamate‐AMPAR system is a fundamental factor in itch processing from the periphery to the SDH under normal conditions.