EN
Experimental results clearly indicate the existence of bidirectional communication between the nervous and immune systems. Changes in the activity of immune system produced by infections or any inflammatory event elicit neurochemical, endocrine and behavioral effects. But the details of those relationships are still not clear. It is hypothesized that afferent branches of nervous vagus may participate in signal transduction to the CNS in response to peripheral infections and/or inflammations, and then activate the hypothalamo-pituitary adrenal axis (HPA) and brain neurotransmitters system. It is commonly accepted that peripheral administration of cytokines or bacterial endotoxin (LPS) to rodents alters their behavior, increases body temperature, activates the HPA axis and affects brain neurochemistry. In the present study we decided to use LPS from Proteus mirabilis (O17 32/57), a Gram-negative bacterium, which is mainly responsible for urinary catheter infection, inflammation of the urinary tract, but also for meningitis, to check it influences on the brain 5-HT system activity and rats anxiety-like behavior in the open field arena (OF). Obtained results indicate that intraperitoneally injected lipopolisaccharide from Proteus mirabilis (O17 32/57) influenced the brain serotonergic system activity. Also, this type of LPS slightly affects animals’ behavior in the OF arena. However, our results are slightly differing from those, observed by other. In our experiment the peak responses in 5-HT system activity appeared around 240 minutes after endotoxin injections.