These studies are in agreement with our prior study showing decreased 5-HT, and increases in SERT, in the NRM in animals with neuropathic pain.6 We extended these prior studies by showing that pharmacological blockade of SERT in the RVM reverses hyperalgesia in this model, providing a physiological role for SERT in the hyperalgesia that develops in chronic muscle pain. Here, SLC6A4 is linked to Pain.