Sonia Martínez-Sanchis

Effects of competition and its outcome on serum testosterone, cortisol and prolactin

In various species, competitive encounters influence hormonal responses in a different way depending on their outcome, victory or defeat. This study aimed to investigate the effects of sports competition and its outcome on hormonal response, comparing it with those displayed in situations involving non-effort and non-competitive effort. To this end, serum testosterone (T), cortisol (C) and prolactin (PRL) were measured in 26 judoists who participated in three sessions (control, judo fight and ergometry). The relationship between hormonal changes and psychological variables before and after the fight were also analysed. Our results showed a hormonal response to competition, which was especially characterized by an anticipatory rise of T and C. Depending on outcome, significant higher C levels were found in winners in comparison to losers through all the competition but not in T or PRL, both groups expending a similar physical effort. Furthermore, similar hormonal responses to the fight and to a non-competitive effort with the same caloric cost were found, other than with PRL. Winners showed a higher appraisal of their performance and satisfaction with the outcome, and perceived themselves as having more ability to win than losers, although there were no significant differences in motivation to win. Finally, the relationships found between T changes in competition and motivation to win, as well as between C response and self-efficacy suggest that in humans hormonal response to competition is not a direct consequence of winning and losing but rather is mediated by complex psychological processes.

Correlating testosterone and fighting in male participants in judo contests

The role of hormones in human aggression is open to debate, but takes on a new urgency owing to the alarming abuse of androgenic anabolic steroids by some sports participants. In this study, video-taped behavior exhibited by 28 male competitors during a judo fight was assessed to analyze its relation to serum testosterone and cortisol levels measured before and after the bouts. A positive relation between testosterone and offensive behaviors was obtained in the sense that the greater the hormonal titer, the greater the number of threats, fights, and attacks. These findings coincide with the pattern of relationships found using observational scales. Conversely, cortisol also presented positive correlations with some of these behavioral categories but did not moderate the relationship between testosterone and competitive behavior. The present results corroborate and extend earlier findings on the role of these hormones in human behavior, giving support to the view that testosterone can be linked to the expression of competitive aggression.

Rewarding Properties of Testosterone in Intact Male Mice: A Pilot Study

The present study examined the rewarding properties of 4-androsten-17beta-ol-3-one testosterone in intact male mice using the conditioned place preference (CPP) technique. In Experiment 1, the pharmacokinetics of 0.8 and 1.2 mg/kg of testosterone were studied to determine the most appropriate temporal interval to test behavior. Additionally, the locomotor activity was recorded to control a possible interfering effect on CPP. The maximum testosterone concentration was registered at 45 min of administration, and no effects on activity were found. In Experiment 2, three groups of male OF-1 mice received four pairings of the least-preferred compartment with testosterone (0.8, 1, or 1.2 mg/kg, SC) for 30 min. On alternate days the preferred compartment was paired with vehicle for 30 min. The control group received vehicle in both compartments. No significant differences between groups were found in the time spent in the drug-paired compartment. However, when separate analyses were performed in conjunction with the color of the drug-paired compartment. CPP was observed only in animals pairing testosterone/black compartment. These results suggest that rewarding properties of testosterone treatment can be observed in male mice; these effects probably being dependent on the environmental cues used as conditioned stimuli.

Activation of serotonergic neurotransmission during the performance of aggressive behavior in rats

High aggression is often linked to lowered serotonin (5-HT) neurotransmission. Although this may hold for high aggression as a trait characteristic of an individual, serotonergic activity is probably increased during performance of aggressive behavior. To test this hypothesis, first, the 5-HT1A agonist alnespirone and gamma aminobutyric acid-A agonist muscimol were administered into the dorsal raphe nucleus. These treatments, which inhibit 5-HT neuronal activity, were shown to decrease performance of aggressive behavior. Second, after a resident-intruder test, the activation of 5-HT neurons (measured by c-fos expression) was increased in high-aggressive rats, compared with low-aggressive rats or control rats that were not subjected to a social confrontation. Results show that performance of aggressive behavior increases 5-HT neuronal activity and that preventing this activation inhibits expression of aggressive behavior.

Psychophysiological responses to the Stroop Task after a maximal cycle ergometry in elite sportsmen and physically active subjects

Physical fitness moderates the psychophysiological responses to stress. This study attempts to determine whether the degree of fitness could affect the response to physical and psychological stress after comparing two groups of men with good physical fitness. Saliva samples from 18 elite sportsmen, and 11 physically active subjects were collected to determine hormonal levels after carrying out a maximal cycle ergometry. Heart rate and skin conductance level were continuously recorded before, during, and after a modified version of the Stroop Color-Word Task. With similar scores in trait anxiety and mood, elite sportsmen had lower basal salivary testosterone, testosterone/cortisol ratio, and HR before an ergometric session than physically active subjects, but no differences were found in salivary cortisol and blood pressure. Salivary testosterone and cortisol responses were lower and testosterone/cortisol ratio responses higher in elite sportsmen. During the Stroop Task, elite subjects showed lower heart rate and skin conductance level over the entire measurement period, and greater heart rate recovery with respect to the baseline values than physically active subjects. The effects of two standardised laboratory stressors on a set of psychophysiological variables were different when elite sportsmen and physically active subjects were compared.

Cocaine-induced locomotor activity is enhanced by exogenous testosterone

Anabolic-androgenic steroids are synthetic derivatives of testosterone, which are increasingly abused by adolescent populations who also abuse psychoactive substances. All these compounds lead to complex behavioral syndromes and the effects of their interactions remain unclear. The main aim of the present study was to determine the influence of testosterone on the locomotor activity-promoting effect of cocaine on male mice in an open field. In the three experiments, animals received two injections: firstly, testosterone or peanut oil, and secondly, cocaine or saline solution. In Experiments 1 and 2, testosterone (or oil) and cocaine (or saline) were injected 45 and 10 min, respectively, prior to activity recording. In the first experiment, we studied the effects of testosterone (2 mg/kg) on locomotor activity induced by different doses of cocaine (2, 4, 8, 10 or 12 mg/kg). In Experiment 2, we explored the effects of supraphysiological doses of testosterone (2, 6, 10 or 14 mg/kg) on animals treated with 10 mg/kg cocaine. Finally, in the third experiment, 14 mg/kg testosterone or vehicle was administered 15, 30, 45 or 75 min before activity data collection to animals that received 10 mg/kg cocaine or saline. Testosterone itself had no effects on spontaneous locomotor activity and, as was expected, cocaine increased locomotor activity dose-dependently. Given together, testosterone enhanced the cocaine-induced hyperactivity although not dose-dependently, the highest effects being found 45 min after testosterone injection. The present study confirmed the existence of an interaction between testosterone and cocaine at the central nervous system.

Long-Term Chronic Treatment with Stanozolol Lacks Significant Effects on Aggression and Activity in Young and Adult Male Laboratory Mice

1. Repeated doses of the anabolic-androgenic steroid stanozolol were assessed for their effects on agonistic behavior, motor activity, and body weight in both young and adult male laboratory mice. 2. Stanozolol significantly increased weight gain in young, but not older subjects, especially at the highest doses. 3. There were, however, no significant differences in motor activity or in ethologically assessed social behavior (including aggression) in young or adult mice.

Similar rewarding effects of testosterone in mice rated as short and long attack latency individuals.

An attempt was made to confirm and extend the findings of an earlier study on the rewarding properties of testosterone in male mice using conditioned place preference (CPP). Previous results had only partially demonstrated such an effect because the reinforcement depended on environmental cues such as the colour of the compartment. High individual variability was evident, suggesting that basal levels of aggressiveness may modulate such effects. Animals were pre‐screened for aggressive behaviour and allocated to short and long attack latency (SAL and LAL) categories. Five days later the CPP procedure started. This involved pre‐conditioning tests, conditioning and post‐conditioning tests. SAL and LAL animals were treated with vehicle, 1 or 2 mg/kg of testosterone. During conditioning (on alternate days), a distinctive floor was paired four times with testosterone. On the intervening days animals were paired with a different floor with vehicle. CPP was clearly observed after testosterone treatment when the colour of the compartment was controlled in both SAL and LAL animals. These results provide additional support for the idea that testosterone and its derivatives have rewarding properties, which could explain processes of dependence.

Effects of immunosuppressive drugs on the cognitive functioning of renal transplant recipients: A pilot study

Some renal transplant patients show cognitive, emotional, and behavioral changes as part of possible neurotoxic effects associated with immunosuppressive medication, especially tacrolimus. This study evaluated effects of immunosuppressive drugs on some cognitive tasks. Patients treated with sirolimus and cyclosporine reported some of the noncognitive side effects related to immunosuppressive treatment. We observed attention and working memory impairment in patients treated with sirolimus or tacrolimus. Performance of cyclosporine-treated subjects was similar to that of healthy volunteer controls. Since the mood, anxiety, and sleep patterns measured were unaffected, it could be concluded that the cognitive deficit found was partly related to treatment.

Neurobiological foundations of multisensory integration in people with autism spectrum disorders: the role of the medial prefrontal cortex

This review aims to relate the sensory processing problems in people with autism spectrum disorders (ASD), especially multisensory integration (MSI), to the role of the medial prefrontal cortex (mPFC) by exploring neuroanatomical findings; brain connectivity and Default Network (DN); global or locally directed attention; and temporal multisensory binding. The mPFC is part of the brain’s DN, which is deactivated when attention is focused on a particular task and activated on rest when spontaneous cognition emerges. In those with ASD, it is hypoactive and the higher the social impairment the greater the atypical activity. With an immature DN, cross-modal integration is impaired, resulting in a collection of disconnected fragments instead of a coherent global perception. The deficit in MSI may lie in the temporal synchronization of neural networks. The time interval in which the stimulation of one sensory channel could influence another would be higher, preventing integration in the typical shorter time range. Thus, the underconnectivity between distant brain areas would be involved in top-down information processes (relying on global integration of data from different sources) and would enhance low level perception processes such as over focused attention to sensory details.