Induction of the PD-1 pathway for Pain therapy: Thiamylal sodium (Trade name: Surital), a general anesthetic,  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, 1/October/2018, 10.24 pm