Oxytocin’s Effects on Sickness Behaviours, Anxiety Responses, and Immune Function in Adult Male Mice
Abstract
The nonapeptide, oxytocin (OT), is implicated in a range of behavioural and physiological functions. However, OT's role in sickness behaviours remains unclear. This thesis examined effects of the OT agonist, carbetocin (CBT), and OT antagonist, L-368,899, on anxiety and locomotor sickness-related behaviours and pro-inflammatory cytokines, TNF-a and IL-6, in adult male CD-1 mice. Animals received 2 intraperitoneal treatment injections. The first treatment was carbetocin, L-368,899, or saline, while the second was lipopolysaccharide (LPS) or saline. Behaviours were evaluated via the light-dark test, and cytokines via immunoassay. OT antagonist treatment attenuated LPS induced perturbations in locomotor and anxiety-like behaviour, but produced no significant effects on cytokines. The 10 mg/kg CBT-saline treatment suppressed locomotion and augmented anxiogenic behaviour, while OT antagonist treatment enhanced locomotor behaviour, and decreased anxiety-like behaviour. The present findings suggest that OT antagonist treatment has anxiolytic effects on basal anxiety-like behaviours, and attenuates the expression of sickness behaviour.