Low Competitive Status Elicits Aggression in Healthy Young Men: Behavioral and Neural Evidence.
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SUBMITTER: Buades-Rotger M
PROVIDER: S-EPMC8599182 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:ContextGhrelin, an acylated peptide hormone secreted from the gut, regulates appetite and metabolism. Elucidating its pattern of secretion in the fed and fasted states is important in the face of the obesity epidemic.ObjectiveOur objective was to examine changes in circulating ghrelin and des-acyl ghrelin in response to meals and fasting using newly developed two-site sandwich assays and sample preservation protocols to allow specific detection of full-length forms.DesignTen-minute sampling was done for 26.5 h during a fed admission with standardized meals and on a separate admission during the final 24 h of a 61.5-h fast and continuing for 2.5 h after terminating the fast.SettingThe study was conducted at the University Hospital General Clinical Research Center.ParticipantsEight male volunteers participated, mean +/- sd age 24.5 +/- 3.7 yr and body mass index 24 +/- 2.1 kg/m(2).Main outcome measuresTen-minute sampling profiles were assessed for ghrelin and des-acyl ghrelin, fed and fasting.ResultsIn the fed state, ghrelin and des-acyl ghrelin showed similar dynamics; both were sharply inhibited by meals and increased at night. During fasting, ghrelin decreased to nadir levels seen postprandially, and des-acyl ghrelin remained near peak levels seen preprandially. Total full-length ghrelin (acyl plus des-acyl) levels remained unchanged.ConclusionsMeals inhibited secretion of both ghrelin and des-acyl ghrelin, yet long-term fasting inhibited acylation but not total secretion. Acylation may be regulated independently of secretion by nutrient availability in the gut or by esterases that cleave the acyl group. These studies highlight the importance of stringent conditions for sample collection and evaluation of full-length ghrelin and des-acyl ghrelin using specific two-site assays.
| S-EPMC2386282 | biostudies-literature
Project description:The effects of genetic polymorphisms on muscle structure and function remain elusive. The present study tested for possible associations of 16 polymorphisms (across ten candidate genes) with fittness and skeletal muscle phenotypes in 17- to 37-year-old healthy Caucasian male endurance (n = 86), power/strength (n = 75) and team athletes (n = 60), and non-athletes (n = 218). Skeletal muscle function was measured with eight performance tests covering multiple aspects of muscular fitness. Along with body mass and height, the upper arm and limb girths, and maximal oxygen uptake were measured. Genotyping was conducted on DNA extracted from blood. Of the 16 polymorphisms studied, nine (spanning seven candidate genes and four gene families/signalling pathways) were independently associated with at least one skeletal muscle fitness measure (size or function, or both) measure and explained up to 4.1% of its variation. Five of the studied polymorphisms (activin- and adreno-receptors, as well as myosine light chain kinase 1) in a group of one to three combined with body height, age and/or group explained up to 20.4% of the variation of muscle function. ACVR1B (rs2854464) contributed 2.0-3.6% to explain up to 14.6% of limb proximal girths. The G allele (genotypes AG and GG) of the ACVR1B (rs2854464) polymorphism was significantly overrepresented among team (60.4%) and power (62.0%) athletes compared to controls (52.3%) and endurance athletes (39.2%), and G allele was also most consistently/frequently associated with muscle size and power. Overall, the investigated polymorphisms determined up to 4.1% of the variability of muscular fitness in healthy young humans.
| S-EPMC9514622 | biostudies-literature
Project description:BACKGROUND: The glucocorticoid (GC) hormone cortisol is the end product of the hypothalamic-pituitary-adrenal axis (HPA axis). Acute psychological stress increases HPA activity and GC release. In humans, chronic disturbances in HPA activity have been observed in affective disorders and in addictive behaviour. Recent research indicates that acute effects of GCs may be anxiolytic and increase reward sensitivity. Furthermore, cortisol acutely influences early cognitive processing of emotional stimuli. METHODS: In order to extend such findings to more complex emotional-cognitive behaviour, the present study tested acute effects of 40 mg cortisol on motivated decision making in 30 healthy young men. RESULTS: Results showed that cortisol indeed increased risky decision making, as predicted. This effect occurred for decisions where making a risky choice could potentially yield a big reward. These results are discussed with respect to currently proposed mechanisms for cortisol's potential anxiolytic effect and GCs' involvement in reward systems.
| S-EPMC2797621 | biostudies-other
Project description:Beliefs and expectations often persist despite evidence to the contrary. Here we examine two potential mechanisms underlying such 'self-reinforcing' expectancy effects in the pain domain: modulation of perception and biased learning. In two experiments, cues previously associated with symbolic representations of high or low temperatures preceded painful heat. We examined trial-to-trial dynamics in participants' expected pain, reported pain and brain activity. Subjective and neural pain responses assimilated towards cue-based expectations, and pain responses in turn predicted subsequent expectations, creating a positive dynamic feedback loop. Furthermore, we found evidence for a confirmation bias in learning: higher- and lower-than-expected pain triggered greater expectation updating for high- and low-pain cues, respectively. Individual differences in this bias were reflected in the updating of pain-anticipatory brain activity. Computational modelling provided converging evidence that expectations influence both perception and learning. Together, perceptual assimilation and biased learning promote self-reinforcing expectations, helping to explain why beliefs can be resistant to change.
| S-EPMC6768437 | biostudies-literature
Project description:IntroductionWorking memory (WM) is a well-known fundamental ability related to various high-level cognitive functions, such as executive functioning, decision-making, and problem-solving. Although previous studies have posited that chronic exercise may improve cognitive functions, its underlying neural mechanisms and whether habitual exercise is associated with individual WM ability remain unclear.MethodsIn the current study, 36 participants reported their habitual physical activity through the International Physical Activity Questionnaire (IPAQ). In addition to assessments of intelligence quotient (IQ), WM storage capacity (K score), and visuomotor coordination capacity, electroencephalogram (EEG) signals were recorded while the participants performed a WM precision task fusing conventional visual and motor retrospective cue (retro-cue) WM tasks.ResultsWe found that greater amounts of and higher frequencies of vigorous-intensity exercise were highly correlated with smaller recall errors in the WM precision task. Contralateral delay activity (CDA), a well-known WM-related event-related potential (ERP) component evoked by the valid retro-cue, predicted individual behavioral recall error. Participants who met the medium or high level of IPAQ criteria (the regular exercise group) showed smaller behavioral recall error and larger CDA than participants who did not meet the criteria (the irregular exercise group). The two groups did not differ in other assessments, such as IQ, WM storage capacity, and visuomotor coordination ability.DiscussionHabitual exercise was specifically correlated with individual differences in WM precision, rather than IQ, WM storage capacity, and visuomotor coordination ability, suggesting potential mechanisms of how modulations of chronic exercise improve cognition through visual and/or motor WM precision.
| S-EPMC10116001 | biostudies-literature
Project description:Study objectivesRecent evidence suggests that certain antidepressants are associated with an increase of periodic leg movements (PLMS) that may disturb sleep. So far, this has been shown in patients clinically treated for depression and in cross-sectional studies for various substances, but not mirtazapine. It is unclear whether antidepressants induce the new onset of PLMS or only increase preexisting PLMS, and whether this is a general property of the antidepressant or only seen in depressed patients. We report here the effect of mirtazapine on PLMS in young healthy men.DesignOpen-labeled clinical trial (NCT00878540) including a 3-week preparatory phase with standardized food, physical activity, and sleep-wake behavior, and a 10-day experimental inpatient phase with an adaptation day, 2 baseline days, and 7 days with mirtazapine.SettingResearch institute.ParticipantsTwelve healthy young (20-25 years) men.InterventionsSeven days of nightly intake (22:00) of 30 mg mirtazapine.Measurements and resultsSleep was recorded on 2 drug-free baseline nights, the first 2 drug nights, and the last 2 drug nights. Eight of the 12 subjects showed increased PLMS after the first dose of mirtazapine. Frequency of PLMS was highest on the first drug night and attenuated over the course of the next 6 days. Three subjects reported transient restless legs symptoms.ConclusionsMirtazapine provoked PLMS in 67% of young healthy males. The effect was most pronounced in the first days. The possible role of serotonergic, noradrenergic and histaminergic mechanisms in mirtazapine-induced PLMS is discussed.
| S-EPMC3624820 | biostudies-literature
Project description:Study objectivesSleep is increasingly recognized to influence a growing array of physiological processes. The relationship between sleep duration and testis size, a marker of male reproductive potential, has not been studied.MethodsThis was a preliminary cross-sectional analysis of the baseline data from 92 healthy men (mean ± standard deviation, age 33 ± 6 years, body mass index [BMI] 24.7 ± 6.1 kg/m2), of whom 66 underwent at-home actigraphy and 47 underwent in-laboratory polysomnography. Sleep duration and architecture were measured by actigraphy and polysomnography, testicular volume by Prader orchidometer, total testosterone by liquid chromatography tandem mass spectrometry, free testosterone by equilibrium dialysis, and luteinizing hormone and follicle-stimulating hormone (FSH) by immunochemiluminometric assay.ResultsSleep duration was correlated with testicular volume (r = .31, P = .046) and with FSH (r = -.30, P = .035), and rapid eye movement sleep was correlated with FSH (r = .44, P = .006). The significance of these findings did not change after adjustment for age and BMI, and were confirmed nonparametrically by resampling. A putative inverse U-shaped relationship between testicular volume and sleep duration was observed by polynomial regression (P = .049), but not with resampling (P = .068).ConclusionsThere is a positive linear and a possible inverse U-shaped relationship between sleep duration and testis volume. Longitudinal or interventional studies manipulating sleep are required to better define causality, and ultimately to establish how much sleep is needed to maximize male reproductive potential.Clinical trial registrationTitle: Hormonal Mechanisms of Sleep Restriction, Registry: ClinicalTrials.gov, Identifier: NCT02256865, URL: https://clinicaltrials.gov/ct2/show/NCT02256865.
| S-EPMC6175801 | biostudies-literature
Project description:Social influence affects us throughout our lives, shaping our attitudes, behaviors, and preferences. Thus, the current study aimed to examine whether key age groups (adolescence versus young adulthood) were associated with differences in neural correlates associated with processing social feedback and conformity (i.e., conflict detection, positive valuation, and mentalizing) among young men. We recruited 153 participants across 5 studies, who completed a social influence task during an fMRI scan. Overall, participants were more likely to conform by changing their ratings when misaligned with others, and adolescents were more likely to conform when misaligned (compared to aligned) with others compared to young adults. Further, we found that adolescents showed increased activity in mentalizing (TPJ, dmPFC) and positive valuation regions (VS, vmPFC), compared to young adults, in response to misalignment with others. In contrast, young adults showed increased activity in conflict detection regions (AI, dACC) when exposed to feedback that they were misaligned with others and when conforming to that feedback. Overall, our results offer initial evidence that adolescent and young adult men engage different neural processes when they find out they are misaligned with others and when conforming to the recommendations of others, and this difference appears to track with brain responses in conflict detection, mentalizing and value regions. DATA STATEMENT: Raw data and analysis codes are available upon request.
| S-EPMC9982604 | biostudies-literature
Project description:IntroductionMifepristone, a competitive glucocorticoid receptor antagonist approved for Cushing syndrome, and ketoconazole, an antifungal and steroidogenesis inhibitor, are both inhibitors of and substrates for cytochrome P450 (CYP3A4). This study evaluated the pharmacokinetic effects of concomitant ketoconazole, a strong CYP3A4 inhibitor, on mifepristone.MethodsIn an open-label, two-period, single-center study, healthy adult men received mifepristone 600 mg orally daily for 12 days (period 1) followed by mifepristone 600 mg daily plus ketoconazole 200 mg orally twice daily for 5 days (period 2). Serial pharmacokinetic blood samples were collected predose and over 24 h postdose on days 12 (period 1) and 17 (period 2). A cross-study comparison (using data on file) further examined whether systemic exposure to mifepristone plus ketoconazole exceeded the exposure following mifepristone 1200 mg orally administered for 7 days.ResultsSixteen subjects were enrolled and 14 completed the study. Concomitant administration with ketoconazole increased the systemic exposure to mifepristone, based on geometric least squares mean ratios, by 28% for C max and 38% for AUC0-24. This increase was 85% and 87% of the exposure observed following mifepristone's highest label dose of 1200 mg/day for C max and AUC0-24, respectively. Adverse events (AEs) were reported in 56.3% (9/16) of subjects during administration of mifepristone alone and in 57.1% (8/14) during combination with ketoconazole. No serious AEs were reported.ConclusionSystemic exposure to mifepristone increased following multiple doses of mifepristone 600 mg daily plus ketoconazole 200 mg twice daily. Little to no increase in AEs occurred. Dose adjustment of mifepristone may be needed when given with ketoconazole.FundingCorcept Therapeutics.
| S-EPMC5656713 | biostudies-literature
Project description:ContextGhrelin is the endogenous agonist for the growth hormone secretagogue receptor (GHS-R). Intravenous administration of ghrelin induces insulin resistance and hyperglycemia and increases the levels of free fatty acids (FFA).ObjectiveTo investigate whether these effects are mediated directly by ghrelin in skeletal muscle tissue.DesignThis study was single blinded, randomized, and placebo controlled. Eight healthy men (25.5 ± 3.1 years) received 240 min of intraarterial ghrelin infusion (4.2 ng × kg(-1) × min(-1)) into one femoral artery and intraarterial placebo infusion into the contralateral artery. Simultaneous blood samples were drawn from both femoral veins and muscle biopsies were obtained from both legs during both a basal period and during a hyperinsulinemic and euglycemic clamp period.ResultsGhrelin significantly elevated venous FFA levels and venous dilution of palmitate, suggestive of increased lipolysis. Glucose metabolism was unchanged, and there were no direct effects on pertinent enzymes in the insulin signaling cascade. The metabolic clearance rate of acyl ghrelin was 12.5 ± 3.3 ml × kg(-1) × min(-1). Acyl and desacyl ghrelin levels both increased.ConclusionsThe results of this study suggest that ghrelin may stimulate lipolysis directly in skeletal muscle.
| S-EPMC5393419 | biostudies-literature