Proteinase-activated receptor 2 is involved in the behavioural changes associated with sickness behaviour

- Delayed onset of reduced sucrose preference in PAR-2-/- mice during LPS-induced sickness behaviour.
- Increased recovery from LPS-induced sickness behaviour in PAR-2-/- mice as seen by locomotor activity and body weight.
- Changes in LPS-induced sickness behaviour not associated with altered PAR2 expression.
- No change in basal behavioural phenotype observed in PAR-2-/- mice.

Proteinase-activated receptor-2 (PAR2) is widely expressed in the CNS but whether it plays a key role in inflammation-related behavioural changes remains unknown. Hence, in the present study we have examined whether PAR2 contributes to behaviour associated with systemic inflammation using PAR2 transgenic mice. The onset of sickness behaviour was delayed and the recovery accelerated in PAR2−/− mice in the LPS-induced model of sickness behaviour. In contrast, PAR2 does not contribute to behaviour under normal conditions. In conclusion, these data suggest that PAR2 does not contribute to behaviour in the normal healthy brain but it plays a role in inflammation-related behavioural changes.

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