The effect of aggressive behavior shaped under social stress of various durations on the production of proinflammatory cytokines by splenic cells was examined on C57BL/6J mice. Aggressive mice were characterized by enhanced production of IL-2 and IFN-γ (released by T helper type 1 cells) and reduced secretion of TNF-α, whose major producers are monocytes and macrophages. Elevation of IL-2 and IFN-γ in aggressive mice resulted from enhancement of spontaneous and Con A-stimulated production, the most pronounced effect was demonstrated by the with a longer period (20 days) of victories. In contrast, spontaneous production of TNF-α was similar in control and aggressive mice, although LPS-stimulated production of this cytokine decreased after 10- and 20-day stress. The possible mechanisms of the changes in cytokine production are discussed.
The selective agonist of type 1 A serotonin receptors 8-hydroxy-2-(di-n-propyl-amino)tetra-lin (8-OH-DPAT) suppressed the immune response. Intraperitoneal administration of 1 mg/kg 8-OH-DPAT to Wistar rats over 2 days after immunization decreased the count of plaque- and rosette-forming cells on day 5. Our results indicate that type 1A serotonin receptors are involved in the realization of the immunosuppressive effects of the serotoninergic system.