ABSTRACT
In the present study we compared the effects of acute (30 min), white and illuminated open field (OF) stress on behavioral, immune and endocrine variables between rats divided into high (HR) and low (LR) responsive to novelty and in a non-divided group. It was found that OF-induced behavioral depression which was in parallel to suppression of both blood and spleen natural killer cell cytotoxicity (NKCC), large granular lymphocyte (LGL) and lymphocyte numbers occurred in stressed LR rats only. There was no significant difference in the plasma level of corticosterone (COR) and testosterone (TST) between HR and LR rats. In contrast, when the HR and LR groups were examined together (the non-divided group), no significant influence of OF stress on behavioral activity or NKCC was observed. These results emphasize that individual differences as measured by spontaneous locomotor activity play the important role for the study of the mechanisms involved in stress-induced immunomodulation and indicate that OF stress-induced behavioral depression in low reactivity animals may be accompanied by impaired defence against viral infections and neoplastic growth, which is functionally related to NKCC.
Subject(s)
Cytotoxicity Tests, Immunologic , Exploratory Behavior , Killer Cells, Natural/immunology , Motor Activity/immunology , Spleen/cytology , Spleen/immunology , Stress, Psychological/blood , Stress, Psychological/immunology , Animals , Corticosterone/blood , Cytotoxicity Tests, Immunologic/methods , Grooming , Leukocyte Count , Lymphocyte Count , Male , Rats , Rats, Wistar , Stress, Psychological/physiopathology , Testosterone/blood , Urination/immunologyABSTRACT
Bilateral electrolytic lesions of the lateral hypothalamic (LH) area in Wistar rats result in a time-dependent blood NK cytotoxicity changes as measured by the 51Cr-release (for entire cell population) and agarose (for a single-cell) assays. NK activity against YAC-1 and K-562 cells shifts from depression through enhancement to another depression on the 2nd, 5th and 21st post-lesion day, respectively, as compared to both LH sham-operated animals and the pre-lesion baselines. This effect is not attributable to malnutrition and dehydration resulting from ingestive impairments evoked by LH lesions. No significant change in NK cytotoxicity was found after destruction of the medial hypothalamus (MH). The results indicate that LH, under normal conditions, which may be considered as a dynamogenic and stressogenic hypothalamic area is essential for proper regulations of NK cytotoxicity at both population and single-cell level.
Subject(s)
Hypothalamic Area, Lateral/immunology , Killer Cells, Natural/immunology , Animals , Behavior, Animal , Cytotoxicity, Immunologic , Electrosurgery , Food Deprivation , Hypothalamus, Middle/immunology , Male , Rats , Rats, Wistar , Tumor Cells, Cultured , Water DeprivationABSTRACT
Teh effect of 48 hr food deprivation on noradrenaline (NA) and dopamine (DA) content in the dorsomedial, ventromedial and arcuate hypothalamic nuclei, in the anterior and posterior part of medial forebrain bundle, in the medial preoptic region, nucleus of diagonal band (septum), and in the central, medial and basal nuclei of the amygdaloid complex was investigated by radioenzymatic assay. It was found that starvation resulted in decreased NA and DA levels in arcuate and ventromedial nuclei, and increased DA content in the posterior medial forebrain bundle. A statistically insignificant increase of DA in the central amygdaloid nucl. was also observed.
