Psychoneuroendocrinology
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Psychoneuroendocrinology · Oct 2008
Comparative StudyLevels and confounders of morning cortisol collected from adolescents in a naturalistic (school) setting.
Salivary cortisol is widely used in research but little is known about the typical, or expected, functioning of the HPA-axis in adolescents in naturalistic settings, nor whether the extensive array of confounders documented in the literature is applicable in this situation. In a school-based study, 2995 15-year-old pupils provided two saliva samples, 30 min apart, in morning sessions timed to capture peak cortisol decline. The collection protocol was a balance between the large sample size obtainable in a school situation and a limited number of samples, constrained by the school timetable. ⋯ Several factors associated with cortisol change differed from those observed for absolute levels. Further adjustment for school clustering affected some associations, particularly time of measurement. This study managed many of the problems found in naturalistic research on cortisol and provides norms for morning cortisol levels in 15-year-old adolescents.
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Psychoneuroendocrinology · Oct 2008
Activation of 5-HT1A autoreceptors in the dorsal raphe nucleus reduces the behavioral consequences of social defeat.
In animal models, serotonin (5-HT) activity contributes to stress-induced changes in behavior. Syrian hamsters (Mesocricetus auratus) exhibit a stress-induced change in behavior in which social defeat results in increased submissive and defensive behavior and a complete loss of normal territorial aggression directed toward a novel, non-aggressive opponent. We refer to this defeat-induced change in agonistic behavior as conditioned defeat. ⋯ In addition, we found that WAY 100635 enhanced conditioned defeat when injected either before social defeat or before testing. These data support the hypothesis that the activity of 5-HT cells in the DRN, as regulated by 5-HT1A autoreceptors, contributes to the formation and display of conditioned defeat. Further, our results suggest that 5-HT release in DRN projection regions augments defeat-induced changes in social behavior.