Subcutaneous formalin produces centrifugal hyperalgesia at a non-injected site via the NMDA-nitric oxide cascade.
Wiertelak EP, Furness LE, Horan R, Martinez J, Maier SF, Watkins LR. Subcutaneous formalin produces centrifugal hyperalgesia at a non-injected site via the NMDA-nitric oxide cascade. Brain Res. 1994 Jun 27; 649(1-2):19-26.