ABSTRACT
The present study demonstrates the involvement of serotonin (5-HT) receptors of the 5-HT 1A type in immunoinhibitory effect of 5-HTergic system of the brain. A selective agonist of 5-HT 1A receptors 8-OH-DPAT (1 mg/kg) induces the immunosuppression, whereas 5-HT 1A blockade with WAY-100635 (1 mg/kg) resulted in immunostimulation. It is also shown that immunomodulating effects of the drugs were dependent on psychoemotional status of animals acquired aggressive or submissive behavior under social conflict conditions. Activation of 5-HT 1A receptors produced a decrease of the immunity in aggressive mice, whereas 5-HT 1A receptor blockade caused immunostimulation in submissive animals.
Subject(s)
Brain/metabolism , Immune Tolerance/immunology , Mood Disorders/immunology , Receptor, Serotonin, 5-HT1A/metabolism , Serotonin/metabolism , Stress, Psychological/immunology , Aggression/drug effects , Aggression/physiology , Animals , Behavior, Animal/drug effects , Behavior, Animal/physiology , Brain/physiopathology , Emotions/physiology , Immune Tolerance/drug effects , Male , Mice , Mice, Inbred C57BL , Mice, Inbred CBA , Mood Disorders/physiopathology , Rats , Rats, Wistar , Serotonin 5-HT1 Receptor Agonists , Serotonin 5-HT1 Receptor Antagonists , Serotonin Antagonists/pharmacology , Serotonin Receptor Agonists/pharmacology , Social Behavior , Stress, Psychological/physiopathologyABSTRACT
The present study demonstrates that: (1) activation of micro -opioid receptors by systemic administration of a highly selective agonist DAGO (100 microg/kg) results in a significant increase in the number of plaque- and rosette-forming cells in the spleen of CBA mice as well as Wistar rats on the 5th day following sheep red blood cells (5 x 10(8)) immunization, (2) the immunostimulatory effect of DAGO is mediated by central mechanisms including the hypothalamus-hypophysis complex; (3) the postsynaptic dopamine (DA) receptors of D2 type are involved in the DAGO-induced immunostimulation since the combined treatment of animals with haloperidol (2 mg/kg), a blocker of DA D2 receptors, and DAGO abolished this effect; (4) the nuclei caudatus and accumbens of the nigrostriatal and mesolimbic DAergic systems, respectively, are implicated in the immune response stimulation caused by DAGO.
Subject(s)
Analgesics, Opioid/pharmacology , Dopamine/metabolism , Enkephalin, Ala(2)-MePhe(4)-Gly(5)-/pharmacology , Immunization , Receptors, Opioid, mu/agonists , Animals , Cerebellar Nuclei/immunology , Cerebellar Nuclei/injuries , Dopamine Antagonists/pharmacology , Erythrocytes/immunology , Haloperidol/pharmacology , Hemolytic Plaque Technique , Hypothalamus/immunology , Hypothalamus/injuries , Immunoglobulin M/biosynthesis , Male , Mice , Mice, Inbred CBA , Neuroimmunomodulation , Nucleus Accumbens/immunology , Nucleus Accumbens/injuries , Pituitary Gland/immunology , Pituitary Gland/injuries , Rats , Rats, Wistar , Rosette Formation , Sheep , Species Specificity , Spleen/drug effectsABSTRACT
The present study has shown that the immune response can be influenced by the reversal of animal's social status. For this purpose testing of agonistic interactions under the sensory contact conditions was performed for pairs of either aggressive or submissive C57BL/6J male mice with preliminary experience of 10 or 20 daily confrontations. Tests continued for 10 or 20 days, respectively. The reversal of aggressive behavior into submissive one in C57BL/6J mice resulted in immunosuppression only following 20 daily confrontations compared to the controls as well as to aggressive males which did not change their behavior and showed the increased immune response. Despite the fact that previous experience of defeat was associated with a reduced immune reaction, the occurrence of aggressive behavior in formerly submissive mice during 10 or 20 tests of daily confrontations produced immunostimulation. It is suggested that changes in the neurochemical pattern of the brain can be considered as an underlying basis for the linkage between the immune response and specific behavioral profile.
Subject(s)
Immunity , Social Dominance , Aggression , Animals , Antibody Formation , Behavior, Animal/physiology , Conflict, Psychological , Male , Mice , Mice, Inbred C57BL , PsychoneuroimmunologyABSTRACT
The production of submissive behavior in C57BL/6J mice during 10 or 20 days of social confrontations resulted in increases in serotonin (5-HT) content in the amygdala, hippocampus, nucleus caudatus, Al1, A10, A9, and hypothalamus. The level of 5-hydroxyindolacetic acid (5-HIAA) was higher in most structures after 20 daily encounters compared to animals tested for 10 days. The ratio 5-HIAA/5-HT was increased in the nucleus raphe, accumbens, A9, and hypothalamus in mice displaying submission during 10 and 20 confrontations. The experience of defeats during 10 days accompanied with 5-HT system activation in a number of brain structures (nucleus raphe, accumbens, and A9) produced immunosuppression. With increasing number of confrontations the ratio 5-HIAA/5-HT was decreased in the same structures and a tendency to the immune response elevation appeared.