Table 1. Summary of functional, morphological and immunological alterations in gene-deleted mouse strains compared to the C57Bl/6 WT group.

Mouse strain	Hyperalgesia	Oedema formation	Histopathological alterations	IL-1β
Tac1−/−	–	–	–	–
Tacr1−/−	↓	–	–	–
Tac4−/−	↓	–	↓	↓
Tac1−/−/Tac4−/−	–	–	↓	↓

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.