The study of the interaction between nervous and immune systems in the mechanism of psychopathology is an important problem of neuroscience. Catalepsy (freezing reaction) is a passive defensive strategy in response to threatening stimuli. An exaggerated form of catalepsy is a syndrome of some grave mental disorders. Both the brain serotonin (5-HT) and immune systems were shown to be involved in the mechanism of catalepsy. Here we compared the effects of two doses (50 or 200 μg/kg, ip) of innate immune system activator, bacterial lipopolysaccharide (LPS), on catalepsy, 5-HT and its main metabolite, 5-hydroxyindole acetic acid (5-HIAA) in the hippocampus, striatum, and midbrain of mice of catalepsy-prone (CBA/Lac and AKR.CBA-D13Mit76) and catalepsy-resistant (AKR/J) strains. The expression of LPS-induced catalepsy as well as 5-HIAA/5-HT ratio in the midbrain and striatum were significantly higher in mice of the catalepsy-prone strains compared with animals of the catalepsy-resistant strains. These results indicated an involvement of the brain 5-HT system in the cataleptogenic effect of LPS and open up new vistas for understanding the nervous-immune mechanism of behavioral disorders.
Keywords: Brain; Catalepsy; Lipopolysaccharide; Mice; Serotonin metabolism.
© 2013.