Euthanasia and anasthesia should lead to unconsciousness. Determining loss of consciousness (LOC) forms the basis of whether a euthanasia or anaesthesia method conforms with animal welfare, as only an unconscious animal feels no pain1.
Recognising LOC in laboratory animals is based on behavioural observations, primarily loss of righting reflex (LRR)2,3, however, this does not prove that an animal is unconscious4. In addition, methods of inducing LOC in mice may be aversive5,6 or painful1,7.
In this project, we propose to investigate the sensory information flow in brain9 in mice and rats during LOC. The changes in brain activity during euthanasia with carbon dioxide (CO2), nitrogen(N2)5 and low atmosphere pressures (LAPS) will be correlated with behaviours (LRR)2,4.
Repeated anaesthesia for experiments instead of using multiple mice is promoted in the 3Rs principles (3Rs Reduce). However, repeated isoflurane anaesthesia is aversive10 whereas sevoflurane may be less so11. This raises the question of how best to repeatedly anaesthetise mice and rats. We will compare isoflurane and sevoflurane in the same experimental paradigm.
These findings should improve the welfare of laboratory rodents during euthanasia and anaesthesia (3Rs Refine).
