3. Central mechanisms of neuroimmune interactions and main questions to the future

Abstract

The modern techniques being applied for the last decade allowed to study gene expression for revealing the activation level of different CNS structures. This led to the determination of spatiotemporal algorithm of brain reactions to stimuli of different nature. Administration of various antigens (T-dependent or T-independent) was shown to cause different patterns of activation of definite hypothalamic structures (by c-Fos protein). Application of stress stimuli alters specific pattern of hypothalamic structures activation causing rearrangement of typical brain reactions to antigen and reduction of their intensity by stress. Antigen administration leads to activation of many CNS structures containing neurons of various ergicity, involved in regulation of sleep/wake cycle, food behaviour, water-salt metabolism, stress reactions etc., in particular orexinergic system. The complex study of the orexin-containing neurons quantity and proproorexin gene expression after lipopolysaccharide application showed their involvement into CNS response to antigen stimuli. The reaction of orexin neurons depends on dose of applied antigen: higher dose shows more prominent shift towards utilization of this neuropeptide than its synthesis. In addition, in orexin receptors expression on cell membranes of CNS structures as well as in peripheral organs after antigen administration also evidence the comprehensiveness and complexity of the response of orexinergic system to antigen stimuli.