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Suppression of Immune Response in Rats by Stress and Drugs Interfering with Metabolism of Serotonin
Author(s) -
BORANIĆ MILIVOJ,
PERICIČIĆ DANKA,
POLJAKBLAŽI MARIJA,
ŠVERKO VIŠNJA,
MAROTTI TANJA
Publication year - 1987
Publication title -
annals of the new york academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.712
H-Index - 248
eISSN - 1749-6632
pISSN - 0077-8923
DOI - 10.1111/j.1749-6632.1987.tb35805.x
Subject(s) - medicine
Rats immunized with sheep erythrocytes were stressed by repeated restraint and/or treated with a precursor of serotonin (5-hydroxytryptophan, 5-HTP) or with an inhibitor of serotonin synthesis (parachlorophenylalanine, PCPA). As expected, repeated stress reduced the plaque-forming cell (PFC) response. Treatment with 5-HTP also reduced the PFC response, and potentiated the immunosuppressive effect of stress. This was accompanied by increased metabolism of serotonin in the brain, as indicated by increased concentration of its metabolite, 5-hydroxyindoleacetic acid (5-HIAA) in cerebral tissue. Treatment with PCPA also suppressed the PFC response, but this suppression was accompanied by decreased levels of brain serotonin and of 5-HIAA. Plasma corticosterone levels were elevated, reaching statistical significance, in rats treated with PCPA. Both drugs suppressed the in vitro PFC response of peripheral blood lymphocytes. Thus, although 5-HTP and PCPA altered serotonin metabolism in the brain in a diametrically opposite manner, their effects on the immune response were the same. Putative central effects of the drugs on serotoninergic regulation of the immune response were apparently obscured by their effects on corticosterone secretion as well as by their direct effects on immunocompetent cells.