OBJECTIVE Glucagon-like peptide-1 (GLP-1) is an incretin hormone known to stimulate glucose-dependent insulin secretion and GLP-1 receptor belongs to Family B of G protein-coupled receptors (GPCRs).The present study examined the biological role of spinal GLP-1 receptors in pain transmission and transduction.METHODS Animal models of chronic pain, molecular biology analysis, and immunehistochemistry staining were employed in the study.RESULTS GLP-1 receptors were widely expressed in the spinal cord and dorsal root ganglia, approximately 1% and 1/10000 of the lungs, respectively.Activation of spinal GLP-1 receptors by the peptide agonists exenatide and GLP-1, as well as small molecule agonists led to specific, efficacious and dose-dependent analgesia in chronic pain including formalin-induced tonic pain, neuropathic pain, bone cancer pain and streptozocin-induced diabetic pain, but not in acute nociception.Long-term administrations of GLP-1 R agonists produced no tolerance to analgesia.Analgesic effects of exenatide and GLP-1 were blocked by the specific GLP-1 R antagonist exendin (9-39).Further signal transduction analysis showed that analgesic effects of exenatide and GLP-1 were acted via the activation of adenylyl cyclase and protein kinase A, same as those in releasing insulin in β cells.CONCLUSION This study, for the first time, identified and validated spinal GLP-1 receptor as a potential target molecule for the treatment of chronic pain without producing tolerance to analgesia.