Summary of functional, morphological and immunological alterations in gene-deleted mouse strains compared to the C57Bl/6 WT group.

Mechanical hyperalgesia was significantly attenuated in Tac4−/− and Tacr1−/− animals, while oedema formation did not differ in any strain. Inflammatory reactions characterised by the histological alterations and changes of cytokine levels were significantly reduced in Tac4−/− and Tac1−/−/Tac4−/− groups.