Effects Of Cortisol Levels Research Articles

Effects of cortisol levels on reproductive success in cattle of different temperaments during fixed-time artificial insemination (FTAI)

The present study was designed to assess the effect of stress on the reproductive performance of cattle. For this purpose, a total of 137 cows were divided into two groups: 65 belonging to the Azores Lydia breed and 72 crossing Aberdeen-Angus with Limousine, free of IBR, Chlamydia and BVD diseases and with a body condition score ranging from 2.75 to 4.0. Eight days before starting the experimental procedures, animals passed through the containment sleeve every other day for routine and human presence. For the synchronization protocol, a progesterone-impregnated controlled internal drug release (CIDR®) insert was placed intravaginally, and an injection of GnRH was given. After 7 days, PGF2α was administered, and the CIDR® was removed. Sixty hours after removal, cows were inseminated once after another injection of GnRH to induce ovulation, and pregnancy diagnosis was performed by ultrasonography 30 days after artificial insemination. Peripheral blood was collected in 5 ml tubes with a Z Serum Sep Clot Activator, and cortisol was measured using the IMMULITE 2000 Immunoassay System ®. Our results indicated significant differences (p≤0.05) in the cortisol levels among both groups (beef crossbred cows vs Azores Lydia) of 4.3±0.3 ng/dl and 5.8±0.4 ng/dl, respectively. The pregnancy results were also significantly different: 63.7% vs 45.6%, respectively, for beef crossbred and "Azores Lydia" cows. The present study clearly demonstrated a negative correlation between cortisol levels and pregnancy rates after fixed-time artificial insemination. The low levels of cortisol observed in the animals and particularly in the Azores Lydia breed, when compared to other studies carried out on these animals, must be due to the passage of the animals in the sleeve, allowing them to habituate to a routine, as well as to human presence.

Dream Recall/Affect and Cortisol: An Exploratory Study.

The effect of cortisol on dreams has been scarcely studied. The aim of this exploratory study was to assess the possible effect of cortisol levels on dream recall/affect, considering, in female subjects, their menstrual cycle phase. Fifteen men and fifteen women were recruited. Saliva samples were used for the detection of cortisol levels. Participants were instructed to provide four saliva samples, during three consecutive days. After awakening, on the second and third day, they were asked whether they could recall the previous night’s dreams and whether these were pleasant or unpleasant. Female subjects followed this procedure twice: firstly, during the luteal phase and, secondly, during the follicular phase of the menstrual cycle. Subjects with higher evening or higher morning cortisol levels tended to show increased dream recall; a non-statistically significant association between morning cortisol levels and positive dream affect was also found. This association acquired statistical significance for salivary morning cortisol levels exceeding the upper normal level of 19.1 nmol/L (OR: 4.444, 95% CI: 1.108–17.830, p-value: 0.039). No connection between menstrual cycle stages and dream recall/affect was detected. In conclusion, cortisol may be a crucial neuromodulator, affecting dream recall and content. Therefore, its effects on sleep and dreams should be further studied.

An Eight Component Decision-Making Model for Problem Gambling:A Systems Approach to Stimulate Integrative Research

Problem Gambling (PG) represents a serious problem for affected individuals, their families and society in general. Previous approaches to understanding PG have been confined to only a subset of the psychobiological factors influencing PG. We present a model that attempts to integrate potential causal factors across levels of organization, providing empirical evidence from the vast literature on PG and complimentary literatures in decision-making and addiction. The model posits that components are arranged systematically to bias decisions in favor of either immediately approaching or avoiding targets affording the opportunity for immediate reward. Dopamine, Testosterone and Endogenous Opioids favor immediate approach, while Serotonin and Cortisol favor inhibition. Glutamate is involved in associative learning between stimuli and promotes the approach response through its link to the DA reward system. GABA functions to monitor performance and curb impulsive decision-making. Finally, while very high levels of Norepinephrine can induce arousal to an extent that is detrimental to sound decision-making, the reactivity of the Norepinephrine system and its effects of Cortisol levels can shift the focus towards long-term consequences, thereby inhibiting impulsive decisions. Empirical evidence is provided showing the effects of each component on PG and decision-making across behavioural, neuropsychological, functional neuroimaging and genetic levels. Last, an effect size analysis of the growing pharmacotherapy literature is presented. It is hoped that this model will stimulate multi-level research to solidify our comprehension of biased decision-making in PG and suggest pharmacological and psychological approaches to treatment.

Effect of cortisol levels on working memory performance in elderly subjects with Alzheimer's disease

Subjects with Alzheimer's disease (AD) have elevated cortisol levels as a result of hypothalamic-pituitary-adrenal (HPA) axis dysfunction. Acute administration of hydrocortisone has been associated with working memory (WM) performance in young adults. To investigate whether cortisol levels are associated with WM performance in subjects with AD. Eighty subjects were included, comprising 40 patients with mild AD and 40 healthy elderly controls. WM was assessed using the Digit Span Backward test (DSB). Saliva samples were collected to determine cortisol levels. AD subjects had poorer performance on the DSB than controls (p=0.002) and also presented higher levels of cortisol than control group (p=0.04). No significant correlation was observed between the DSB and cortisol levels in both groups (r= -0.29). In this study, elevated cortisol levels were not associated with poorer WM performance in patients with AD or in healthy elderly subjects.