Alternatives for Analgesiometric Tests in Animals: The Feasibility to Reduce Discomfort by Anaesthesia

Abstract

Animal pain and nociception studies have greatly contributed to our understanding of acute and chronic  pain processing and thereby contributed to the reduction of suffering of patients in pain. In classic analgesiometric  tests in conscious animals, animal suffering is inevitable as pain behaviour is the primary outcome.  Therefore, the feasibility of refining analgesiometric tests by anaesthesia is reviewed. The influence  on analgesiometric tests of different anaesthetics is described. Other objective primary outcome measures  than pain behaviour, including quantification of neural activation with c-fos and functional MRI (fMRI), are  suggested to reduce animal discomfort for pain testing. In conclusion, reflex analgesiometric tests may be  refined by choosing the right anaesthetics and alternative outcome measures such as c-fos or fMRI. Complex,  higher order pain behaviour testing still requires conscious animals and can currently not be refined  by the use of anaesthetics.