Mechanistic insights into how Vasoactive Intestinal Peptide (PHM27/VIP) attenuates pain: PHM27/VIP, a peptide hormone consisting of 28 amino acids that promotes contractility, vasodilation, glycogenosis, arterial blood pressure and others, increases the expression of PD-L1, attenuates acute and chronic pain, and suppresses mechanical and thermal hypersensitivity and inhibits nociceptive neuron excitability via up-regulation of its target gene, 10/May/2019, 6.21 am