Behavioral and neurochemical responses in mice bearing tumors submitted to social stress.
Through the proinflammatory cytokines secreted in response to inflammation or injury, the immune system produces physiological and behavioral alterations. This study analyzes the effects on behavior, mononuclear proliferative response and central monoamine activity in response to the inoculation of tumor cells in mice submitted to social stress. Two groups of male OF1 mice were used, one of which was inoculated with B16 melanoma cells. Both groups were subdivided into two new groups, with one being submitted to social stress through sensory contact model with a selected aggressive subject, and the other being handled without social interaction. Subjects were exposed to social stress for a 24-h period, with three 5 min intervals of direct physical interaction, where the behavior was recorded and assessed. One hour after the stress and/or handling, they were put down and samples taken for physiological assessment. Significant behavioral changes were found in subjects with implanted tumors, mainly characterized by an increase in avoidance behavior and a decrease in immobility, defense-submission and non-social exploration behavior, coupled with an increase in the spleen mononuclear cell proliferative response. Similarly, an increase was observed in the density of dopamine(2) (D(2))-receptors in the striatum (SRT) and an increase in dopaminergic (DOPAC/DA) and serotonergic (5HIAA/5HT) turnover in the hypothalamus. The increase in the density of D(2)-receptors in the SRT coincides with the decrease in some behaviors with a predominant motor component. The results indicate significant changes in the defensive strategy used to cope with situations of intense social stress in mice bearing tumors.
Vegas
O
O
Area of Psychobiology, Department of Basic Psychological Processes and Their Development, Faculty of Psychology, Basque Country University, Avenida de Tolosa 70, San Sebastián 20018, Spain.
Beitia
G
G
Sánchez-Martin
J R
JR
Arregi
A
A
Azpiroz
A
A
D000704:Analysis of Variance; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D001665:Binding Sites; D015306:Biogenic Monoamines / Q000032:analysis; D001923:Brain Chemistry; D002455:Cell Division; D045744:Cell Line, Tumor; D007398:Interpersonal Relations; D008214:Lymphocytes / Q000276:immunology / Q000502:physiology; D008297:Male; D008545:Melanoma / Q000737:chemistry / Q000503:physiopathology* / Q000523:psychology; D051379:Mice; D008810:Mice, Inbred C57BL; D011897:Random Allocation; D017448:Receptors, Dopamine D2 / Q000378:metabolism; D013315:Stress, Psychological / Q000503:physiopathology* / Q000523:psychology; D013997:Time Factors
D015306:Biogenic Monoamines; D017448:Receptors, Dopamine D2