GRIN1 and disease of the tendon: The finding that ionotropic glutamate receptor agonism increases inflammatory cytokine production [40–42] in human synoviocytes and chondrocytes suggests that glutamate receptor modulation may be a viable means of therapeutically targeting the synoviocyte in painful tendinopathy; this is consistent with our study’s finding in terms of the co-localisation of NMDAR1 and CD206.