PubMed · 558650
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R Lore, K Flannelly. 1977. Rat societies.. https://doi.org/10.1038/scientificamerican0577-106
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Sleep is generally considered to be a process of recovery from prior wakefulness. In addition to being affected by the duration of the waking period, sleep architecture and sleep EEG also depend on the quality of wakefulness. In the present experiment, we examined how sleep is affected by different social stimuli (social conflict and sexual interaction). Male C57BL/6J mice were placed in the cage of an aggressive dominant male or an estrous female for 1 h in the middle of the light phase. The conflict with an aggressive male had a pronounced NREM sleep-promoting effect. EEG slow wave activity, a measure of NREM sleep intensity, was increased for about 6 h and NREM sleep time was significantly increased for 12 h. REM sleep was strongly suppressed during the remainder of the light phase after the conflict, followed by a rebound later in the recovery phase. The sexual interaction, in contrast, had only mild effects. Both NREM sleep and REM sleep were somewhat suppressed shortly after the interaction. In a separate group of mice, blood samples were taken to measure prolactin and corticosterone. The results suggest that the temporary suppression of REM sleep following the social stimuli may be partly due to elevated corticosterone. The different effects of the social stimuli on NREM sleep are not easily explained by differences in the hormone responses. In conclusion, although both social conflict and sexual interaction induce a strong physiological activation, only social conflict has a strong stimulatory effect on NREM sleep mechanisms.
The present study examined if olfactory bulbectomy (OBX) altered defensive behaviors on the elevated plus-maze and the open-field differently in male and female rats. Similar increases in defensive behaviors in male and female rats were observed in both tests following OBX. No significant correlations were detected between defensive behaviors and activity, supporting the hypothesis that some behavioral changes following OBX may be due to decreased defensive behaviors and not increased activity.
This study examines the correlations between serum lipid levels and psychological distress. There were 4444 consecutive attendees of general health clinics who participated in the study. Psychological symptoms were measured by the Taiwanese version of the Symptoms Check List 90, revised (T-SCL-90-R). Levels of fasting serum lipids, including total cholesterol, total triglycerides and high-density lipoprotein cholesterol (HDL-C), were determined. Multiple linear regression analyses, with adjustment for confounders, revealed that the concentration of HDL-C had significant inverse associations with scores of depression, somatization and phobic anxiety. Women with an HDL-C level lower than 35 mg/dl scored significantly higher on depression, interpersonal sensitivity, phobia, anxiety, somatization and aggressive hostility, while subjects with a total cholesterol concentration lower than 160 mg/dl scored significantly higher on anxiety, aggressive hostility, phobia, and psychoticism. This study provides, for the first time, comprehensive data derived from the Taiwanese population on the link between lipids and psychological symptoms, revealing a reverse correlation between depression and serum concentrations of HDL-C.