ABSTRACT
The current study investigated the role of estrogen receptor alpha (Esr1) in maternal memory in rats, comparing the induction and retention responses of Esr1 knockout (KO) and wild type (WT) nulliparous rats towards foster pups. Thirty days after completion of induction testing, subjects were tested for the retention of maternal care in their home cage and then for maternal behaviors in a novel cage. Both WT and Esr1 KO females displayed similar latencies to respond to foster young during the initial induction testing. Likewise, reinduction latencies to display full maternal responsiveness were similar in the Esr1 KO and WT groups during maternal memory testing in the home cage. However, in the novel cage testing WT subjects displayed modest modifications in maternal care. WT females had shorter latencies to first retrieve and mouth a test pup. These findings suggest that while Esr1 does not appear to affect the establishment of maternal care or the display of maternal memory, it may modulate aspects of pup-directed behaviors associated with the reinduction of maternal care in female rats.
Subject(s)
Estrogen Receptor alpha/genetics , Maternal Behavior/physiology , Memory/physiology , Animals , Female , Gene Knockout Techniques , Male , Mothers/psychology , Nesting Behavior/physiology , Parity , Pregnancy , Rats , Rats, Sprague-Dawley , Rats, TransgenicABSTRACT
BACKGROUND: Attention-deficit hyperactivity disorder (ADHD) is a developmental disorder whose three main symptoms are impulsiveness, inattention, and hyperactivity. Researchers have proposed that the central deficit in ADHD is one of poor response inhibition. The present studies were designed to look at the functioning of the hypothalamic-pituitary-adrenal (HPA) axis in response to mental stress in aggressive ADHD subjects participating in a longitudinal study of various psychosocial treatments. METHODS: Pretest and posttest morning salivary samples for cortisol determination were collected from subjects given a battery of tests. RESULTS: The study shows that ADHD subjects who maintained their diagnosis over the first year of the study had a blunted response to the stressor in comparison to those ADHD subjects who no longer retained the disorder 1 year later. CONCLUSIONS: The data suggest that an impaired response to stress may be a marker for the more developmentally persistent form of the disorder.
Subject(s)
Attention Deficit Disorder with Hyperactivity/diagnosis , Hydrocortisone/analysis , Aggression/psychology , Attention Deficit Disorder with Hyperactivity/epidemiology , Attention Deficit Disorder with Hyperactivity/psychology , Child , Child, Preschool , Comorbidity , Conduct Disorder/diagnosis , Conduct Disorder/epidemiology , Conduct Disorder/psychology , Female , Follow-Up Studies , Humans , Male , Psychological Tests , Saliva/chemistry , Stress, Psychological/diagnosis , Stress, Psychological/psychologyABSTRACT
Assessments of cortisol levels in saliva have been widely used by both researchers and clinicians as an index of adrenal functioning. Quarterly measurements of morning and evening cortisol levels were determined in a longitudinal study of 147 participants (72 women and 75 men) followed for 1 year each. The analysis of salivary cortisol revealed no significant gender or age differences in the sample. There was a sequence effect in quarterly cortisol values with a progressive decrease in serial measurements, especially notable in the morning values; as well as a seasonal variation in cortisol levels with significantly higher levels found in winter and fall, compared with spring and summer. The findings in this study suggest that repeated saliva sampling and seasonal variation in cortisol levels may independently affect adrenal response and, therefore, need to be accounted for in longitudinal studies.