Anabolic-androgenic steroid treatment induces behavioral disinhibition and downregulation of serotonin receptor messenger RNA in the prefrontal cortex and amygdala of male mice

Aggression, Aggression-Related Psychopathologies and Their Models

Neural mechanisms of aggression and violence are often studied in the laboratory by means of animal models. A multitude of such models were developed over the last decades, which, however, were rarely if ever compared systematically from a psychopathological perspective. By overviewing the main models, I show here that the classical ones exploited the natural tendency of animals to defend their territory, to fight for social rank, to defend themselves from imminent dangers and to defend their pups. All these forms of aggression are functional and adaptive; consequently, not necessarily appropriate for modeling non-natural states, e.g., aggression-related psychopathologies. A number of more psychopathology-oriented models were also developed over the last two decades, which were based on the etiological factors of aggression-related mental disorders. When animals were exposed to such factors, their aggressiveness suffered durable changes, which were deviant in the meaning that they broke the evolutionarily conserved rules that minimize the dangers associated with aggression. Changes in aggression were associated with a series of dysfunctions that affected other domains of functioning, like with aggression-related disorders where aggression is just one of the symptoms. The comparative overview of such models suggests that while the approach still suffers from a series of deficits, they hold the important potential of extending our knowledge on aggression control over the pathological domain of this behavior.

Fmr1 exon 14 skipping in late embryonic development of the rat forebrain

BACKGROUND

Fragile X syndrome, the major cause of inherited intellectual disability among men, is due to deficiency of the synaptic functional regulator FMR1 protein (FMRP), encoded by the FMRP translational regulator 1 (FMR1) gene. FMR1 alternative splicing produces distinct transcripts that may consequently impact FMRP functional roles. In transcripts without exon 14 the translational reading frame is shifted. For deepening current knowledge of the differential expression of Fmr1 exon 14 along the rat nervous system development, we conducted a descriptive study employing quantitative RT-PCR and BLAST of RNA-Seq datasets.

RESULTS

We observed in the rat forebrain progressive decline of total Fmr1 mRNA from E11 to P112 albeit an elevation on P3; and exon-14 skipping in E17-E20 with downregulation of the resulting mRNA. We tested if the reduced detection of messages without exon 14 could be explained by nonsense-mediated mRNA decay (NMD) vulnerability, but knocking down UPF1, a major component of this pathway, did not increase their quantities. Conversely, it significantly decreased FMR1 mRNA having exon 13 joined with either exon 14 or exon 15 site A.

CONCLUSIONS

The forebrain in the third embryonic week of the rat development is a period with significant skipping of Fmr1 exon 14. This alternative splicing event chronologically precedes a reduction of total Fmr1 mRNA, suggesting that it may be part of combinatorial mechanisms downregulating the gene's expression in the late embryonic period. The decay of FMR1 mRNA without exon 14 should be mediated by a pathway different from NMD. Finally, we provide evidence of FMR1 mRNA stabilization by UPF1, likely depending on FMRP.

Association between nandrolone and behavioral alterations: A systematic review of preclinical studies

BACKGROUND AND AIM

In recent years the expanding misuse of Nandrolone among non-athletes, particularly adolescent males is a prevalent global concern due to its adverse effects. This article provides a summary of the experimental studies to clarify the relationship between Nandrolone exposure and behavioral and cognitive performances.

MATERIALS AND METHODS

The present systematic review was conducted using PubMed, Embase and ScienceDirect databases, from 2000 to 2020, using the following key terms: Nandrolone AND Cognition, Nandrolone AND Learning, Nandrolone AND Memory, Nandrolone AND (Synaptic plasticity or Hippocampal synaptic plasticity), Nandrolone AND (Aggression or Aggressive-like behavior), Nandrolone AND (Anxiety or Anxiety-like behavior), Nandrolone AND (Depression or Depressive-like behavior).

RESULTS

33 qualified papers were selected from the 2498 sources found. Of the 33 cases, 32 (96.97%) were males while only 1 (3.03%) was female and male. From 33 selected articles 8 reported studies were related to spatial memory, 2 reported studies were related to avoidance memory, 11 studies reported information on synaptic plasticity, 11 reported studies were related to aggressive behavior, 8 reported studies were related to aggressive behavior and 6 reported studies were related to depression.

CONCLUSION

Nandrolone can change spatial ability, avoidance memory and hippocampal synaptic plasticity. Also, Nandrolone exposure produces variable effects on behavioral function such as aggression, depression and anxiety. This despite the fact that the results are contradictory. These discrepancies might be due to the differences in sex, age, dosage and treatment duration, and administration route. However, the negative results are more common than the published positive ones.

Testosterone works through androgen receptors to modulate neuronal response to anxiogenic stimuli

Testosterone (T) exerts anxiolytic effects through functional androgen receptors (ARs) in rodents. T treatment of castrated mice reduces anxiety-like behavior in wild-type (WT) males, but not males with a spontaneous mutation that renders AR dysfunctional (testicular feminization mutation, Tfm). Using Cre-LoxP technology we created males carrying induced dysfunctional AR allele (induced TFM; iTfm) to determine the brain regions responsible for T-induced anxiolysis. Adult WT and iTfm mice were castrated and T treated. Castrated WTs given a blank capsule (WT + B) served as additional controls. Mice were later exposed to the anxiogenic light/dark box, sacrificed and their brains processed for immediate early gene cFos immunoreactivity. Analyses revealed that T treatment increased cFos-expressing neurons in the basolateral amygdala (blAMY) of WT males, but not in iTfm males, which did not differ from WT + B mice. In contrast, WT + T males displayed fewer cFos + cells than iTfm + T or WT + B groups in the suprachiasmatic nucleus of the hypothalamus (SCN). No effects of genotype or hormone were seen in cFos expression in the hippocampus, medial prefrontal cortex, paraventricular nucleus of the hypothalamus, oval and anterodorsal bed nucleus of the stria terminalis, or dorsal periaqueductal grey. AR immunohistochemistry indicated that ∼65 % of cells in the blAMY and SCN were AR + in WT males, so AR could act directly within neurons in these regions to modulate the animals' response to anxiogenic stimuli. Because absence of a functional AR did not affect cFos response to mild stress in the other brain regions, they are unlikely to mediate androgen's anxiolytic effects.

Anabolic steroids-induced delirium: A case report

INTRODUCTION

Anabolic steroids are commonly used by athletes, body builders, and young adults to improve muscle strength. Deleterious effects of anabolic steroids on physical health are well-established. Psychiatric aspects are of particular importance and include psychosis, delirium, mania, depression, and aggression. We describe the case of a young gentleman who was managed as a case of androgenic steroid induced delirium.

PATIENT CONCERN

A 33-year-old gentleman presented with increased aggression, hostility, and destructive impulses. He was a regular user of testosterone propionate, testosterone cyprionate and trenbolone acetate up to 200 mg daily in injectable form. His mental status examination showed labile effect, flight of ideas and persecutory delusions. Physical examination was positive for atrophic testes. Laboratory results showed a decreased plasma testosterone level of 9.59 nmol/l (10.4-37.4 nmol/l). Sex Hormone Binding Globulin was 23.8 nmol/l (18.3-54.1 nmol/l) and bioavailable testosterone was 5.110 nmol/l (4.36-14.30 nmol/l).

DIAGNOSIS

He was diagnosed as a case of anabolic steroids induced delirium.

INTERVENTIONS AND OUTCOME

Patient was treated with regular haloperidol and quetiapine after which his sensorium, speech and behavior improved. He was discharged on haloperidol 7.5 mg and quetiapine 700 mg daily.

CONCLUSION

The purpose of this case report is to emphasize on the neuropsychiatric effects and management of anabolic steroids manifested by delirium, increased aggression, hostility, and destructive impulses.

Serotonin type-3 receptors differentially modulate anxiety and aggression during withdrawal from adolescent anabolic steroid exposure

Male Syrian hamsters (Mesocricetus auratus) administered anabolic/androgenic steroids during adolescent development display increased aggression and decreased anxious behavior during the adolescent exposure period. Upon withdrawal from anabolic/androgenic steroids, this neurobehavioral relationship shifts and hamsters exhibit decreased aggression and increased anxious behavior. This study investigated the hypothesis that alterations in anterior hypothalamic signaling through serotonin type-3 receptors modulate the behavioral shift between adolescent anabolic/androgenic steroid-induced aggressive and anxious behaviors during the withdrawal period. To test this, hamsters were administered anabolic/androgenic steroids during adolescence then withdrawn from drug exposure for 21 days and tested for aggressive and anxious behaviors following direct pharmacological manipulation of serotonin type-3 receptor signaling within the latero-anterior hypothalamus. Blockade of latero-anterior hypothalamic serotonin type-3 receptors both increased aggression and decreased anxious behavior in steroid-treated hamsters, effectively reversing the pattern of behavioral responding normally observed during anabolic/androgenic steroid withdrawal. These findings suggest that the state of serotonin neural signaling within the latero-anterior hypothalamus plays an important role in behavioral shifting between aggressive and anxious behaviors following adolescent exposure to anabolic/androgenic steroids.

Serotonin Receptor 1A Variation Is Associated with Anxiety and Agonistic Behavior in Chimpanzees

Serotonin is a neurotransmitter that plays an important role in regulating behavior and personality in humans and other mammals. Polymorphisms in genes coding for the serotonin receptor subtype 1A (HTR1A), the serotonin transporter (SLC6A4), and the serotonin degrading enzyme monoamine oxidase A (MAOA) are associated with anxiety, impulsivity, and neurotic personality in humans. In primates, previous research has largely focused on SLC6A4 and MAOA, with few studies investigating the role of HTR1A polymorphic variation on behavior. Here, we examined variation in the coding region of HTR1A across apes, and genotyped polymorphic coding variation in a sample of 214 chimpanzees with matched measures of personality and behavior. We found evidence for positive selection at three amino acid substitution sites, one in chimpanzees-bonobos (Thr26Ser), one in humans (Phe33Val), and one in orangutans (Ala274Gly). Investigation of the HTR1A coding region in chimpanzees revealed a polymorphic site, where a C/A single nucleotide polymorphism changes a proline to a glutamine in the amino acid sequence (Pro248Gln). The substitution is located in the third intracellular loop of the receptor, a region important for serotonin signal transduction. The derived variant is the major allele in this population (frequency 0.67), and is associated with a reduction in anxiety, decreased rates of male agonistic behavior, and an increase in socio-positive behavior. These results are the first evidence that the HTR1A gene may be involved in regulating social behavior in chimpanzees and encourage further systematic investigation of polymorphic variation in other primate populations with corresponding data on behavior.

Neuropsychiatric and Behavioral Involvement in AAS Abusers. A Literature Review

Background and Objectives: Anabolic androgenic steroids (AASs) are a complex group of molecules that include both steroidal androgens and synthetic compounds, derived from testosterone. AASs are commonly used to support pharmacological therapy in cases of primary or secondary hypogonadism, major burns, and neoplastic cachexia. Their prolonged and supra-physiological consumption can provoke several adverse effects on various organs and systems. Among these, the physiopathological mechanisms that induce neuropsychiatric disorders related to AAS abuse are poorly known. For this reason, the proposed review aims to retrace the pathway of action of testosterone to focus on the effects on the central nervous system and specifically highlight the effects of AASs on neuropsychiatric and behavioral functions, as well as on lifestyle. Materials and Methods: This review was conducted using PubMed and Google Scholar databases. On these database websites, we searched for articles from 1 January 1980 to March 2019 using the key terms: "AAS," "Anabolic Androgenic Steroids," "brain," and "neurology." Results: The use of AASs through self-administration yields circulating androgens levels, inducing neuron apoptosis, which is linked to thinner cortex and, in general, less cortical volume. The same alterations affect the putamen. These differences were more evident when correlated with longer use. From a functional point of view, prolonged AAS consumption seemed to be related to lower connectivity between amygdala and frontal, striatal, limbic, hippocampal and visual cortical areas. On the other hand, AAS use seems to negatively condition the positive effects of the sport exercise, reducing its important anti-apoptotic and pro-proliferative functions on the hippocampus, implicated in anxiolytic control. Conclusion: This review clarifies the major aspects of the side effects related to AAS use/abuse highlighting the complex mechanisms on neuropsychiatric and cognitive pathological alterations and also the emotional and behavioral dysfunctions.

Anabolic-androgenic steroids and cognitive effort discounting in male rats

Anabolic-androgenic steroids (AAS) are drugs of abuse that impair behavior and cognition. In a rodent model of AAS abuse, testosterone-treated male rats expend more physical effort, by repeatedly pressing a lever for a large reward in an operant discounting task. However, since modern society prioritizes cognitive over physical effort, it is important to determine if AAS limit cognitive effort. Here we tested the effects of AAS on a novel cognitive-effort discounting task. Each operant chamber had 3 nose-pokes, opposite 2 levers and a pellet dispenser. Rats pressed a lever to illuminate 1 nose-poke; they responded in the illuminated nose-poke to receive sugar pellets. For the 'easy' lever, the light remained on for 1 s, and a correct response earned 1 pellet. For the 'hard' lever, the light duration decreased from 1 s to 0.1 s across 5 blocks of trials, and a correct response earned 4 pellets. As the duration of the nose-poke light decreased, all rats decreased their choice of the hard lever in a modest discounting curve. Task accuracy also decreased significantly across the 5 blocks of trials. However, there was no effect of testosterone on choice of the hard lever or task accuracy. Antagonism of dopamine D1 or D2 receptors had no effect on lever choice or task accuracy. However, serotonin depletion significantly decreased preference for the hard lever, and impaired task accuracy. Thus, physical effort discounting depends on dopamine activity, while cognitive effort discounting task is sensitive to serotonin. AAS impair physical effort discounting, but not cognitive effort discounting.

Ghrelin and aggressive behaviours-Evidence from preclinical and human genetic studies

Aggressive behaviour is of crucial importance in the defence for limited resources including food and mates and involves central serotonin as well as dopamine signalling. As ghrelin modulates food intake and sexual behaviour we initially investigated the hypothesis that central ghrelin signalling regulates aggressive behaviour in the resident intruder paradigm in male mice. Moreover, interaction between ghrelin signalling and serotonergic, noradrenergic as well as dopaminergic neurotransmission in aggression was investigated. The relevance of ghrelin for human aggression per se as well as for aggression induced by alcohol was evaluated in a human genetic association study comprising young men (n = 784) from the normal population assessed for anti-social behaviours. The present study demonstrates that central ghrelin infusion, but not ghrelin administered systemically, increases aggression. Moreover aggressive behaviour is decreased by pharmacological suppression of the growth hormone secretagogue receptor-1 A (GHSR-1A) by JMV2959. As indicated by the ex vivo biochemical data serotonin, rather than dopamine or noradrenaline, in amygdala may have central roles for the ability of JMV2959 to reduce aggression. This link between central serotonin, GHSR-1A and aggression is further substantiated by the behavioural data showing that JMV2959 cannot decrease aggression following depletion of central serotonin signalling. The genetic association study demonstrates that males carrying the Leu72Leu genotype of the pre-pro-ghrelin gene and displaying hazardous alcohol use are more aggressive when compared to the group carrying the Met-allele. Collectively, this contributes to the identification of central ghrelin pathway as an important modulator in the onset of aggressive behaviours in male mice.

The Impact of Hippocampal Sex Hormones Receptors in Modulation of Depressive-Like Behavior Following Chronic Anabolic Androgenic Steroids and Exercise Protocols in Rats

The aim of this study was to evaluate alterations in depressive-like behaviors in rats following chronic administration of a supraphysiological dose of anabolic androgenic steroids (AASs) as well as exposure to a prolonged exercise protocol. The role of hippocampal sex hormones receptors in the modulation of depressive-like behavior was also assessed. A total of 48 male Wistar albino rats were divided into six groups: control, exercise (1 h/day, five consecutive days), nandrolone-decanoate (ND, 20 mg/kg/week, in a single dose), exercise plus ND, testosterone-enanthate (TE, 20 mg/kg/week, in a single dose), and exercise plus TE. After the 6-week protocols were complete, the rats underwent behavioral testing in the tail suspension test (TST). Rats were sacrificed for the collection of blood samples, to determine sex hormones levels, and isolation of the hippocampus, to determine [androgen receptors (AR) and estrogen receptors α (ERα)] expression. ND and TE treatment induced significant depressive-like behavior, opposing the antidepressant effect of exercise. Chronic TE administration elevated testosterone (T) and dihydrotestosterone (DHT) serum levels, and this was augmented by exercise. In contrast, ND and exercise alone did not alter T or DHT levels. There were no changes in serum estradiol levels in any of the groups. Immunohistochemical analysis showed that exercise reduced AR immunoreactivity in all hippocampal regions and increased the ERα expression in the CA1, dentate gyrus (DG), and total hippocampal sections, but not in the CA2/3 region. AASs administration increased AR expression in all hippocampal regions, although not the total hippocampal section in the TE group and did not significantly decrease ERα. The hippocampal AR/ERα expression index was lowered while parvalbumin (PV)-immunoreactivity was enhanced by exercise. AASs administration increased the AR/ERα index and reduced PV-immunoreactivity in the hippocampus. The number of PV-immunoreactive neurons negatively correlated with the antidepressant effects and the AR/ERα ratio. Our results suggest a potential role of the numerical relationship between two sex hormones receptors (stronger correlation than for each individual receptor) in the regulation of depressive-like behavior via the hippocampal GABAergic system in rats, which allow better understanding of the hippocampal sex hormones receptors role in modulation of depressive-like behavior.

Potential risks related to anabolic steroids use on nervous, cardiovascular and reproductive systems disorders in men

Anabolic steroids (AS) have been a subject of intensive research for the last several decades. Due to wide use of AS in pharmacological treatment and in professional and amateur sport, it is, hence, worthwhile to describe the biochemical mechanism of the effects of AS usage in humans and its potential health risks. In this work, the relationship between diet and its effect on the level of testosterone in blood is described. Testosterone affects the nervous system, however, there is need for further researches to examine the influence of AS therapy on emotional and cognitive functioning. AS therapy has known negative effects on the cardiovascular system: cardiac hypertrophy can occur, blood pressure can vastly increased, thrombotic complications can come about. These effects are observed not only in patients who are treated with AS, but also in athletes. The paper also describes the relationship between AS and reproductive system diseases. Decreased libido and erectile dysfunction are only some of the many side effects of an incorrect AS treatment.

Defining the Construct of Synthetic Androgen Intoxication: An Application of General Brain Arousal

Synthetic androgens (i. e., anabolic-androgenic steroids) are the primary component to the majority of problematic appearance and performance enhancing drug (APED) use. Despite evidence that these substances are associated with increased risk for aggression, violence, body image disturbances, and polypharmacy and can develop a pattern of chronic use consistent with drug dependence, there are no formal definitions of androgen intoxication. Consequently, the purpose of this paper is to establish a testable theory of androgen intoxication. We present evidence and theorize that synthetic androgen intoxication can be defined by a pattern of poor self-regulation characterized by increased propensity for a range of behaviors (e.g., aggression, sex, drug seeking, exercise, etc.) via androgen mediated effects on general brain arousal. This theory posits that androgens reduce threshold for emotional reactivity, motor response, and alertness to sensory stimuli and disrupt inhibitory control over the behaviors associated with synthetic androgen use. These changes result from alteration to basic neurocircuitry that amplifies limbic activation and reduces top-down cortical control. The implications for this definition are to inform APED specific hypotheses about the behavioral and psychological effects of APED use and provide a basis for establishing clinical, legal, and public health guidelines to address the use and misuse of these substances.

Impact of anger emotional stress before pregnancy on adult male offspring

Previous studies have reported that maternal chronic stress or depression is linked to an increased risk of affective disorders in progeny. However, the impact of maternal chronic stress before pregnancy on the progeny of animal models is unknown. We investigated the behaviors and the neurobiology of 60-day-old male offspring of female rats subjected to 21 days of resident-intruder stress before pregnancy. An anger stressed parental rat model was established using the resident-intruder paradigm and it was evaluated using behavioral tests. Anger stressed maternal rats showed a significant increase in locomotion and aggression but a reduction in sucrose preference. Offspring subjected to pre-gestational anger stress displayed enhanced aggressive behaviors, reduced anxiety, and sucrose preference. Further, offspring subjected to pre-gestational stress showed significant impairments in the recognition index (RI) on the object recognition test and the number of platform crossings in the Morris water maze test. The monoaminergic system was significantly altered in pre-gestationally stressed offspring, and the expression of phosphorylated cyclic adenosine monophosphate response element binding protein (P-CREB), brain-derived neurotrophic factor (BDNF), and serotonin transporter (SERT) levels in pre-gestational stressed offspring were altered in some brain regions. Fluoxetine was used to treat pre-gestational stressed maternal rats and it significantly reduced the changes caused by stress, as evidenced by both behaviors and neural biochemical indexes in the offspring in some but not all cases. These findings suggest that anger stress before pregnancy could induce aggressive behaviors, cognitive deficits, and neurobiological alterations in offspring.

Different Molecular/Behavioral Endophenotypes in C57BL/6J Mice Predict the Impact of OX1 Receptor Blockade on Binge-Like Ethanol Intake

Ethanol (EtOH) research has focused on stages of dependence. It is of paramount importance to more deeply understand the neurobehavioral factors promoting increased risk for EtOH binge drinking during the early stages of the addiction cycle. The first objective of this study was to evaluate whether C57BL/6J mice showing high drinking in the dark (DID) exhibit neurobehavioral traits known to contribute to EtOH binge-drinking disorders. Comparing high vs. low drinkers (HD/LD), we evaluated different types of basal anxiety-like responses, EtOH preference and sensitivity to the reinforcing properties of EtOH, and basal mRNA expression of the OX1/OX2 receptors (OX1r/OX2r) within the prefrontal cortex (PFC) and the nucleus accumbens (NAcc). Additionally, we tested binge drinking by LD/HD in response to a selective OX1r antagonist following intermittent episodes of DID (iDID). We report that DID consistently segregates two neurobehavioral endophenotypes, HD vs. LD, showing differences in neophobia and/or impulsivity/compulsivity traits. Additionally, HD mice show decreased basal OX1r and OX2r mRNA expression within the NAcc and elevated OX1r within the PFC. Exposure to several intermittent episodes of EtOH DID triggered a rapid increase in EtOH intake over time in LD mice matching that observed in HD mice. Despite HD/LD endophenotypes did not show differences in EtOH intake, they still predicted the response to a pharmacological challenge with a selective OX1r antagonist. The present data underscore the relevance of HD/LD endophenotypes stemming from DID procedures for exploring neurobehavioral processes underlying the early stages of the addiction cycle and EtOH binge-drinking disorders.

The Role of Anabolic Androgenic Steroids in Disruption of the Physiological Function in Discrete Areas of the Central Nervous System

Anabolic-androgenic steroids (AAS) abuse is often associated with a wide spectrum of adverse effects. These drugs are frequently abused by adolescents and athletes for esthetic purposes, as well as for improvement of their endurance and performances. In this literature review, we evaluated the correlation between AAS and anxiety or aggression. Two pathways are thought to be involved in AAS-induced behavioral disorders. Direct pathway via the amygdalo-fugal pathway, which connects the central nucleus of the amygdala to the brainstem, is involved in cognitive-emotive and homeostatic processes. The latter is modified by chronic AAS use, which subsequently leads to increased anxiety. Indirect pathways via the serotonergic, dopaminergic, and glutamatergic signals which are modified by AAS abuse in latero-anterior hypothalamus and can mediate the aggressive behavior. In conclusion, the molecular mechanisms underlying the behavioral alterations following AAS abuse is unclear and remains ambiguous as additional long-term studies aimed to understand the precise mechanisms are required.

The role of central and medial amygdala in normal and abnormal aggression: A review of classical approaches

The involvement of the amygdala in aggression is supported by overwhelming evidence. Frequently, however, the amygdala is studied as a whole, despite its complex internal organization. To reveal the role of various subdivisions, here we review the involvement of the central and medial amygdala in male rivalry aggression, maternal aggression, predatory aggression, and models of abnormal aggression where violent behavior is associated with increased or decreased arousal. We conclude that: (1) rivalry aggression is controlled by the medial amygdala; (2) predatory aggression is controlled by the central amygdala; (3) hypoarousal-associated violent aggression recruits both nuclei, (4) a specific upregulation of the medial amygdala was observed in hyperarousal-driven aggression. These patterns of amygdala activation were used to build four alternative models of the aggression circuitry, each being specific to particular forms of aggression. The separate study of the roles of amygdala subdivisions may not only improve our understanding of aggressive behavior, but also the differential control of aggression and violent behaviors of various types, including those associated with various psychopathologies.

Efeitos dos anabolizantes sobre a densidade de neurônios dos núcleos da base

RESUMO Objetivos: Pouco se sabe sobre a atuação dos esteroides androgênicos anabolizantes (EAA) no cérebro humano e, por isso, resolvemos estudar a perda neuronal causada pelo uso e abuso de EAA em camundongos. Métodos: Utilizamos 60 camundongos da linhagem Swiss, sendo 30 machos e 30 fêmeas, divididos em três grupos: 20 animais foram tratados com Deposteron® (cipionato de testosterona); outros 20 animais foram tratados com Winstrol Depot® (stanozolol); os últimos 20 animais foram tratados com solução salina. Todos foram submetidos à natação por 15 minutos. Finalizado o tratamento, os animais foram sacrificados pelo método de inalação de Halotano. Os encéfalos foram retirados e armazenados em solução de formaldeído a 4% por 24 horas. De cada encéfalo foram retiradas amostras homotípicas da região média do cérebro em cortes frontais para que pudéssemos avaliar as áreas estabelecidas para este estudo. Resultados: As análises da estimativa dos perfis celulares mostraram que houve uma diminuição do número de perfis no núcleo pálido dos animais machos tratados com Winstrol Depot®. Conclusão: Esses resultados nos permitem inferir que o uso inadequado e sem orientação médica de EAA pode levar a degenerações celulares.

Vasopressin differentially modulates aggression and anxiety in adolescent hamsters administered anabolic steroids

Adolescent Syrian hamsters (Mesocricetus auratus) treated with anabolic/androgenic steroids display increased offensive aggression and decreased anxiety correlated with an increase in vasopressin afferent development, synthesis, and neural signaling within the anterior hypothalamus. Upon withdrawal from anabolic/androgenic steroids, this neurobehavioral relationship shifts as hamsters display decreased offensive aggression and increased anxiety correlated with a decrease in anterior hypothalamic vasopressin. This study investigated the hypothesis that alterations in anterior hypothalamic vasopressin neural signaling modulate behavioral shifting between adolescent anabolic/androgenic steroid-induced offensive aggression and anxiety. To test this, adolescent male hamsters were administered anabolic/androgenic steroids and tested for offensive aggression or anxiety following direct pharmacological manipulation of vasopressin V1A receptor signaling within the anterior hypothalamus. Blockade of anterior hypothalamic vasopressin V1A receptor signaling suppressed offensive aggression and enhanced general and social anxiety in hamsters administered anabolic/androgenic steroids during adolescence, effectively reversing the pattern of behavioral response pattern normally observed during the adolescent exposure period. Conversely, activation of anterior hypothalamic vasopressin V1A receptor signaling enhanced offensive aggression in hamsters exposed to anabolic/androgenic steroids during adolescence. Together, these findings suggest that the state of vasopressin neural development and signaling in the anterior hypothalamus plays an important role in behavioral shifting between aggression and anxiety following adolescent exposure to anabolic/androgenic steroids.

Social stress in adolescents induces depression and brain-region-specific modulation of the transcription factor MAX

MAX is a conserved constitutive small phosphoprotein from a network of transcription factors that are extensively studied in tumorigenesis and whose functions affect cell proliferation, differentiation and death. Inspired by its higher expression during development and in regions involved in emotional behaviors, we hypothesized its involvement in cerebral changes caused by early-life stress. We studied the effects of repeated social stress during adolescence on behaviors and on MAX and its putative partner MYC. Thirty-day-old C57BL/6 male mice underwent brief daily social defeat stress from an adult aggressor for 21 days. Following social stress episodes and housing in social groups after each defeat, adolescent mice exhibit depressive-like, but not anxiety-like behaviors and show higher MAX nuclear immunoreactivity in hippocampal (HC) but not prefrontal cortical (PFC) neurons. Conversely, MAX immunoreactivity is lower in the striatum (ST) of defeated adolescents. The positive correlation between MAX and MYC levels in the PFC revealed disruptions in both the HC and ST. The changes in MAX protein levels are not due to differential gene expression or protein degradation in those regions, suggesting that posttranscriptional modifications occurred. These findings indicate that repeated, brief social defeat in adolescent male mice, combined with group housing, is a useful protocol to study a subtype of depression that is dissociated from generalized (non-social) anxiety. To our knowledge, this is the first report of an association between dysregulation of the MAX-MYC network in the brain and a behavior, suggesting a novel approach for exploiting the neuroplasticity associated with depression.

Exogenous Testosterone, Aging, and Changes in Behavioral Response of Gonadally Intact Male Mice

This study tested the hypothesis that aging significantly affects the influence of exogenous testosterone on neurobehavior in gonadally intact male mice. Groups of prepubertal and aged male mice received daily vehicle or testosterone propionate (TP; 2.5 or 5.0 mg/kg intraperitoneal [i.p.]) for 21 days. Behaviors were assessed on days 1 and 21. Weight gain was significant in prepubertal mice. Locomotion and rearing increased in prepubertal mice after first dose and decreased after last dose of TP. Rearing was suppressed in aged mice throughout. Suppression of grooming occurred in both age groups at day 21. Significant increase in working memory in both age groups was seen in the radial-arm maze (at specific doses) and in prepubertal mice in the Y-maze. Elevated plus maze test showed mixed anxiolytic/anxiogenic effects. Aged mice had higher serum testosterone. In conclusion, age is an important determinant for the influence of exogenous testosterone on behavior in gonadally intact male mice.

Anger Emotional Stress Influences VEGF/VEGFR2 and Its Induced PI3K/AKT/mTOR Signaling Pathway

Objective. We discuss the influence of anger emotional stress upon VEGF/VEGFR2 and its induced PI3K/AKT/mTOR signal pathway. Methods. We created a rat model of induced anger (anger-out and anger-in) emotional response using social isolation and resident-intruder paradigms and assessed changes in hippocampus' VEGF content, neuroplasticity, and the PI3K/AKT/mTOR signaling pathway. Results. The resident-intruder method successfully generated anger-out and anger-in models that differed significantly in composite aggression score, aggression incubation, open field behavior, sucrose preference, and weight gain. Anger emotional stress decreased synaptic connections and VEGFR2 expression. Anger emotional stress led to abnormal expression of VEGF/VEGFR2 mRNA and protein and disorderly expression of key factors in the PI3K/AKT/mTOR signal pathway. Fluoxetine administration ameliorated behavioral abnormalities and damage to hippocampal neurons caused by anger emotional stress, as well as abnormal expression of some proteins in VEGF/VEGFR2 and its induced PI3K/AKT/mTOR signal pathway. Conclusion. This research provides a detailed classification of anger emotion and verifies its influence upon VEGF and the VEGF-induced signaling pathway, thus providing circumstantial evidence of mechanisms by which anger emotion damages neurogenesis. As VEGFR2 can promote neurogenesis and vasculogenesis in the hippocampus and frontal lobe, these results suggest that anger emotional stress can result in decreased neurogenesis.

Mad men, women and steroid cocktails: a review of the impact of sex and other factors on anabolic androgenic steroids effects on affective behaviors

RATIONALE

For several decades, elite athletes and a growing number of recreational consumers have used anabolic androgenic steroids (AAS) as performance enhancing drugs. Despite mounting evidence that illicit use of these synthetic steroids has detrimental effects on affective states, information available on sex-specific actions of these drugs is lacking.

OBJECTIVES

The focus of this review is to assess information to date on the importance of sex and its interaction with other environmental factors on affective behaviors, with an emphasis on data derived from non-human studies.

METHODS

The PubMed database was searched for relevant studies in both sexes.

RESULTS

Studies examining AAS use in females are limited, reflecting the lower prevalence of use in this sex. Data, however, indicate significant sex-specific differences in AAS effects on anxiety-like and aggressive behaviors, interactions with other drugs of abuse, and the interplay of AAS with other environmental factors such as diet and exercise.

CONCLUSIONS

Current methods for assessing AAS use have limitations that suggest biases of both under- and over-reporting, which may be amplified for females who are poorly represented in self-report studies of human subjects and are rarely used in animal studies. Data from animal literature suggest that there are significant sex-specific differences in the impact of AAS on aggression, anxiety, and concomitant use of other abused substances. These results have relevance for human females who take these drugs as performance-enhancing substances and for transgender XX individuals who may illicitly self-administer AAS as they transition to a male gender identity.

Lipid peroxidation and apoptotic response in rat brain areas induced by long-term administration of nandrolone: the mutual crosstalk between ROS and NF-kB

The aim of this study was to evaluate the played by oxidative stress in the apoptotic response in different brain areas of rats chronically treated with supra-physiological doses of nandrolone decanoate (ND). Immunohistochemical study and Western blot analysis were performed to evaluate cells' apoptosis and to measure the effects of expression of specific mediators, such as NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells), Bcl-2 (B-cell lymphoma 2), SMAC/DIABLO (second mitochondria-derived activator of caspases/direct IAP-binding protein with low PI) and VMAT2 (vesicular monoamine transporter 2) on apoptosis. The results of the present study indicate that a long-term administration of ND promotes oxidative injury in rat brain specific areas. A link between oxidative stress and NF-κB signalling pathways is supported by our results. In addition to high levels of oxidative stress, we consistently observed a strong immunopositivity to NF-κB. It has been argued that one of the pathways leading to the activation of NF-κB could be under reactive oxygen species (ROS)-mediated control. In fact, growing evidence suggests that although in limited doses, endogenous ROS may play an activating role in NF-κB signalling, while above a certain threshold, they may negatively impact upon this signalling. However, a mutual crosstalk between ROS and NF-κB exists and recent studies have shown that ROS activity is subject to negative feedback regulation by NF-κB, and that this negative regulation of ROS is the means through which NF-κB counters programmed cells.

Chronic Exposure to Androgenic-Anabolic Steroids Exacerbates Axonal Injury and Microgliosis in the CHIMERA Mouse Model of Repetitive Concussion

Concussion is a serious health concern. Concussion in athletes is of particular interest with respect to the relationship of concussion exposure to risk of chronic traumatic encephalopathy (CTE), a neurodegenerative condition associated with altered cognitive and psychiatric functions and profound tauopathy. However, much remains to be learned about factors other than cumulative exposure that could influence concussion pathogenesis. Approximately 20% of CTE cases report a history of substance use including androgenic-anabolic steroids (AAS). How acute, chronic, or historical AAS use may affect the vulnerability of the brain to concussion is unknown. We therefore tested whether antecedent AAS exposure in young, male C57Bl/6 mice affects acute behavioral and neuropathological responses to mild traumatic brain injury (TBI) induced with the CHIMERA (Closed Head Impact Model of Engineered Rotational Acceleration) platform. Male C57Bl/6 mice received either vehicle or a cocktail of three AAS (testosterone, nandrolone and 17α-methyltestosterone) from 8-16 weeks of age. At the end of the 7th week of treatment, mice underwent two closed-head TBI or sham procedures spaced 24 h apart using CHIMERA. Post-repetitive TBI (rTBI) behavior was assessed for 7 d followed by tissue collection. AAS treatment induced the expected physiological changes including increased body weight, testicular atrophy, aggression and downregulation of brain 5-HT1B receptor expression. rTBI induced behavioral deficits, widespread axonal injury and white matter microgliosis. While AAS treatment did not worsen post-rTBI behavioral changes, AAS-treated mice exhibited significantly exacerbated axonal injury and microgliosis, indicating that AAS exposure can alter neuronal and innate immune responses to concussive TBI.

The Historical Development of Immunoendocrine Concepts of Psychiatric Disorders and Their Therapy

Relationships between the central nervous, immune and endocrine systems are a focus of psychiatric research, particularly in depression and schizophrenia. The field has long antecedents. Observed phenomena attributable to these relationships date back to the Neolithic era. Immunoendocrine theories in the broadest sense are recorded in antiquity. In the 19th century, Kraepelin and Wagner-Jauregg reported pioneering clinical observations in psychiatric patients. Von Basedow, Addison and Cushing described psychiatric symptoms in patients suffering from endocrine diseases. The 20th century opened with the identification of hormones, the first, adrenaline, chemically isolated independently by Aldrich und Takamine in 1901. Berson and Yalow developed the radioimmunoassay (RIA) technique in 1959 making it possible to measure levels of hormones and cytokines. These developments have enabled great strides in psychoimmunoendocrinology. Contemporary research is investigating diagnostic and therapeutic applications of these concepts, for example by identifying biomarkers within the endocrine and immune systems and by synthesizing and testing drugs that modulate these systems and show antidepressant or antipsychotic properties.

Maternal testosterone exposure increases anxiety-like behavior and impacts the limbic system in the offspring

During pregnancy, women with polycystic ovary syndrome (PCOS) display high circulating androgen levels that may affect the fetus and increase the risk of mood disorders in offspring. This study investigated whether maternal androgen excess causes anxiety-like behavior in offspring mimicking anxiety disorders in PCOS. The PCOS phenotype was induced in rats following prenatal androgen (PNA) exposure. PNA offspring displayed anxiety-like behavior in the elevated plus maze, which was reversed by flutamide [androgen receptor (AR) blocker] and tamoxifen [selective estrogen receptor (ER) modulator]. Circulating sex steroids did not differ between groups at adult age. The expression of serotonergic and GABAergic genes associated with emotional regulation in the amygdala was consistent with anxiety-like behavior in female, and partly in male PNA offspring. Furthermore, AR expression in amygdala was reduced in female PNA offspring and also in females exposed to testosterone in adult age. To determine whether AR activation in amygdala affects anxiety-like behavior, female rats were given testosterone microinjections into amygdala, which resulted in anxiety-like behavior. Together, these data describe the anxiety-like behavior in PNA offspring and adult females with androgen excess, an impact that seems to occur during fetal life, and is mediated via AR in amygdala, together with changes in ERα, serotonergic, and GABAergic genes in amygdala and hippocampus. The anxiety-like behavior following testosterone microinjections into amygdala demonstrates a key role for AR activation in this brain area. These results suggest that maternal androgen excess may underpin the risk of developing anxiety disorders in daughters and sons of PCOS mothers.

Effects of anabolic-androgens on brain reward function

Androgens are mainly prescribed to treat several diseases caused by testosterone deficiency. However, athletes try to promote muscle growth by manipulating testosterone levels or assuming androgen anabolic steroids (AAS). These substances were originally synthesized to obtain anabolic effects greater than testosterone. Although AAS are rarely prescribed compared to testosterone, their off-label utilization is very wide. Furthermore, combinations of different steroids and doses generally higher than those used in therapy are common. Symptoms of the chronic use of supra-therapeutic doses of AAS include anxiety, depression, aggression, paranoia, distractibility, confusion, amnesia. Interestingly, some studies have shown that AAS elicited electroencephalographic changes similar to those observed with amphetamine abuse. The frequency of side effects is higher among AAS abusers, with psychiatric complications such as labile mood, lack of impulse control and high violence. On the other hand, AAS addiction studies are complex because data collection is very difficult due to the subjects' reticence and can be biased by many variables, including physical exercise, that alter the reward system. Moreover, it has been reported that AAS may imbalance neurotransmitter systems involved in the reward process, leading to increased sensitivity toward opioid narcotics and central stimulants. The goal of this article is to review the literature on steroid abuse and changes to the reward system in preclinical and clinical studies.

Lipoic acid and pentoxifylline mitigate nandrolone decanoate-induced neurobehavioral perturbations in rats via re-balance of brain neurotransmitters, up-regulation of Nrf2/HO-1 pathway, and down-regulation of TNFR1 expression

Behavioral perturbations associated with nandrolone decanoate abuse by athletes and adolescents may be attributed to oxidative stress and inflammation. However, the underlying mechanisms are not yet fully explored. On the other hand, the natural antioxidant lipoic acid can pass the blood brain barrier and enhance Nrf2/HO-1 (nuclear factor erythroid-2 related factor 2/heme oxygenase-1) pathway. In addition, the phosphodiesterase-IV inhibitor xanthine derivative pentoxifylline has a remarkable inhibitory effect on tumor necrosis factor-alpha (TNF-α). Therefore, this study aimed at investigation of the possible protective effects of lipoic acid and/or pentoxifylline against nandrolone-induced neurobehavioral alterations in rats. Accordingly, male albino rats were randomly distributed into seven groups and treated with either vehicle, nandrolone (15mg/kg, every third day, s.c.), lipoic acid (100mg/kg/day, p.o.), pentoxifylline (200mg/kg/day, i.p.), or nandrolone with lipoic acid and/or pentoxifylline. Rats were challenged in the open field, rewarded T-maze, Morris water maze, and resident-intruder aggression behavioral tests. The present findings showed that nandrolone induced hyperlocomotion, anxiety, memory impairment, and aggression in rats. These behavioral abnormalities were accompanied by several biochemical changes, including altered levels of brain monoamines, GABA, and acetylcholine, enhanced levels of malondialdehyde and TNF-α, elevated activity of acetylcholinesterase, and up-regulated expression of TNF-α receptor-1 (TNFR1). In addition, inhibited catalase activity, down-regulated Nrf2/HO-1 pathway, and suppressed acetylcholine receptor expression were observed. Lipoic acid and pentoxifylline combination significantly mitigated all the previously mentioned deleterious effects mainly via up-regulation of Nrf2/HO-1 pathway, inhibition of TNF-α and down-regulation of TNFR1 expression. In conclusion, the biochemical and histopathological findings of this study revealed the protective mechanisms of lipoic acid and pentoxifylline against nandrolone-induced behavioral changes and neurotoxicity in rats.

Serotonin depletion-induced maladaptive aggression requires the presence of androgens

The sex hormone testosterone and the neurotransmitter serotonin exert opposite effects on several aspects of behavior including territorial aggression. It is however not settled if testosterone exerts its pro-aggressive effects by reducing serotonin transmission and/or if the anti-aggressive effect of serotonin requires the presence of the androgen. Using the resident intruder test, we now show that administration of the serotonin synthesis inhibitor para-chlorophenylalanine (300 mg/kg x 3 days) increases the total time of attack as well as the percentage amount of social behavior spent on attack but not that spent on threat - i.e. that it induces a pattern of unrestricted, maladaptive aggression - in gonadectomized C57Bl/6 male mice receiving testosterone replacement; in contrast, it failed to reinstate aggression in those not given testosterone. Whereas these results suggest the pro-aggressive effect of testosterone to be independent of serotonin, and not caused by an inhibition of serotonergic activity, the pCPA-induced induction of maladaptive aggression appears to require the presence of the hormone. In line with these findings, pCPA enhanced the total time of attack as well the relative time spent on attacks but not threats also in wild-type gonadally intact male C57Bl/6 mice, but failed to reinstate aggression in mice rendered hypo-aggressive by early knock-out of androgen receptors in the brain (ARNesDel mice). We conclude that androgenic deficiency does not dampen aggression by unleashing an anti-aggressive serotonergic influence; instead serotonin seems to modulate aggressive behavior by exerting a parallel-coupled inhibitory role on androgen-driven aggression, which is irrelevant in the absence of the hormone, and the arresting of which leads to enhanced maladaptive aggression.

Anabolic/androgenic steroid administration during adolescence and adulthood differentially modulates aggression and anxiety

Anabolic/androgenic steroid (AAS) use remains high in both teens and adults in the U.S. and worldwide despite studies showing that AAS use is associated with a higher incidence of aggression and anxiety. Recently we showed that chronic exposure to AAS through adolescence increases aggression and decreases anxious behaviors, while during AAS-withdrawal aggression is lowered to species-normative levels and anxiety increases. AAS exposure is known to differentially alter behaviors and their underlying neural substrates between adults and adolescents and thus the current study investigated whether exposure to AAS during adulthood affects the relationship between aggression and anxiety in a manner similar to that previously observed in adolescents. Male hamsters were administered a moderate dose of AAS (5.0mg/kg/day×30days) during adolescence (P27-56) or young adulthood (P65-P94) and then tested for aggression and anxiety during AAS exposure (i.e., on P57 or P95) and during AAS withdrawal (i.e., 30days later on P77 or P115). Adolescent exposure to AAS increased aggressive responding during the AAS exposure period and anxiety-like responding during AAS withdrawal. Neither behavior was similarly influenced by adult exposure to AAS. Adult AAS exposure produced no difference in aggressive responding during AAS exposure (P95) or AAS withdrawal (P115); however, while AAS exposure during adulthood produced no difference in anxiety-like responding during AAS exposure, adult hamsters administered AAS were less anxious than vehicle control animals following AAS withdrawal. Together these data suggest that the aggression and anxiety provoking influence of AAS are likely a developmental phenomenon and that adult exposure to AAS may be anxiolytic over the long term.

Coupling of the HPA and HPG axes in the context of early life adversity in incarcerated male adolescents

The effects of early life adversity can be observed across the lifespan, and the hypothalamic-pituitary-adrenal (HPA) and hypothalamic-pituitary-gonadal (HPG) axes could be mechanistic intermediaries underlying this phenomenon. The current study examined 50 adolescent males aged 12-18 in a maximum-security correctional and treatment setting. Saliva samples were collected five times a day for 2 days and assayed for cortisol, testosterone, and DHEA. Youth completed semi-structured life stress interviews and self-reports of child maltreatment to index adversity. When youth had higher testosterone levels, they had higher cortisol and DHEA levels, indicating positive "coupling" of the HPA-HPG axes. In addition, children experiencing greater life adversity had tighter coupling of the HPA-HPG axes. Additional analyses hint that coupling may be driven largely by HPG axis functioning. Results indicate that positive coupling of the HPA-HPG axis is observed within incarcerated adolescents, especially for those with the greatest life stress.

Sex and exercise interact to alter the expression of anabolic androgenic steroid-induced anxiety-like behaviors in the mouse

Anabolic androgenic steroids (AAS) are taken by both sexes to enhance athletic performance and body image, nearly always in conjunction with an exercise regime. Although taken to improve physical attributes, chronic AAS use can promote negative behavior, including anxiety. Few studies have directly compared the impact of AAS use in males versus females or assessed the interaction of exercise and AAS. We show that AAS increase anxiety-like behaviors in female but not male mice and that voluntary exercise accentuates these sex-specific differences. We also show that levels of the anxiogenic peptide corticotrophin releasing factor (CRF) are significantly greater in males, but that AAS selectively increase CRF levels in females, thus abrogating this sex-specific difference. Exercise did not ameliorate AAS-induced anxiety or alter CRF levels in females. Exercise was anxiolytic in males, but this behavioral outcome did not correlate with CRF levels. Brain-derived neurotrophic factor (BDNF) has also been implicated in the expression of anxiety. As with CRF, levels of hippocampal BDNF mRNA were significantly greater in males than females. AAS and exercise were without effect on BDNF mRNA in females. In males, anxiolytic effects of exercise correlated with increased BDNF mRNA, however AAS-induced changes in BDNF mRNA and anxiety did not. In sum, we find that AAS elicit sex-specific differences in anxiety and that voluntary exercise accentuates these differences. In addition, our data suggest that these behavioral outcomes may reflect convergent actions of AAS and exercise on a sexually differentiated CRF signaling system within the extended amygdala.

Genetic mapping of escalated aggression in wild-derived mouse strain MSM/Ms: association with serotonin-related genes

The Japanese wild-derived mouse strain MSM/Ms (MSM) retains a wide range of traits related to behavioral wildness, including high levels of emotionality and avoidance of humans. In this study, we observed that MSM showed a markedly higher level of aggression than the standard laboratory strain C57BL/6J. Whereas almost all MSM males showed high frequencies of attack bites and pursuit in the resident-intruder test, only a few C57BL/6J males showed aggressive behaviors, with these behaviors observed at only a low frequency. Sexually mature MSM males in their home cages killed their littermates, or sometimes female pair-mates. To study the genetic and neurobiological mechanisms that underlie the escalated aggression observed in MSM mice, we analyzed reciprocal F1 crosses and five consomic strains of MSM (Chr 4, 13, 15, X and Y) against the background of C57BL/6J. We identified two chromosomes, Chr 4 and Chr 15, which were involved in the heightened aggression observed in MSM. These chromosomes had different effects on aggression: whereas MSM Chr 15 increased agitation and initiation of aggressive events, MSM Chr 4 induced a maladaptive level of aggressive behavior. Expression analysis of mRNAs of serotonin receptors, serotonin transporter and Tph2, an enzyme involved in serotonin synthesis in seven brain areas, indicated several differences among MSM, C57BL/6J, and their consomic strains. We found that Tph2 expression in the midbrain was increased in the Chr 4 consomic strain, as well as in MSM, and that there was a strong positive genetic correlation between aggressive behavior and Tph2 expression at the mRNA level. Therefore, it is possible that increased expression of the Tph2 gene is related to escalated aggression observed in MSM.

Chronic nandrolone decanoate exposure during adolescence affects emotional behavior and monoaminergic neurotransmission in adulthood

Nandrolone decanoate, an anabolic androgen steroid (AAS) illicitly used by adult and adolescent athletes to enhance physical performance and body image, induces psychiatric side effects, such as aggression, depression as well as a spectrum of adverse physiological impairments. Since adolescence represents a neurodevelopmental window that is extremely sensitive to the detrimental effects of drug abuse, we investigated the long-term behavioral and neurophysiological consequences of nandrolone abuse during adolescence. Adolescent rats received daily injections of nandrolone decanoate (15 mg/kg, i.m.) for 14 days (PND 40-53). At early adulthood (PND 68), forced swim, sucrose preference, open field and elevated plus maze tests were performed to assess behavioral changes. In vivo electrophysiological recordings were carried out to monitor changes in electrical activity of serotonergic neurons of the dorsal raphe nucleus (DRN) and noradrenergic neurons of the locus coeruleus (LC). Our results show that after early exposure to nandrolone, rats display depression-related behavior, characterized by increased immobility in the forced swim test and reduced sucrose intake in the sucrose preference test. In addition, adult rats presented anxiety-like behavior characterized by decreased time and number of entries in the central zone of the open field and decreased time spent in the open arms of the elevated plus maze. Nandrolone decreased the firing rate of spontaneously active serotonergic neurons in the DRN while increasing the firing rate of noradrenergic neurons in the LC. These results provide evidence that nandrolone decanoate exposure during adolescence alters the emotional profile of animals in adulthood and significantly modifies both serotonergic and noradrenergic neurotransmission.

Chronic exposure to a predator or its scent does not inhibit male-male competition in male mice lacking brain serotonin

Although it is well-known that defective signaling of the 5-HT system in the brain and stressful stimuli can cause psychological disorders, their combined effects on male–male aggression and sexual attractiveness remain unknown. Our research aimed at examining such effects using tryptophan hydroxylase 2 (Tph2) knockout male mice vs. a rat- or rat scent-based chronic stress model. Tph2^+/+ and Tph2^−/− male mice were placed individually into the rat home cage (rat), a cage containing soiled rat bedding (rat scent) or a cage containing fresh bedding (control) for 5 h every other day for 56 consecutive days. In Tph2^+/+ male mice, rat-exposure decreased male–male aggression and sexual attractiveness of urine odor relative to either rat scent-exposure or control; and rat scent-exposure decreased aggression rather than sexual attractiveness of urine odor compared with control. However, such dose-dependent and long-lasting behavioral inhibitory effects vanished in Tph2^−/− male mice. RT-PCR assay further revealed that putative regulatory genes, such as AR, ERα and GluR4 in the prefrontal cortex, and TrkB-Tc and 5-HTR1A in the hippocampus, were down-regulated at the mRNA level in either rat- or rat scent-exposed Tph2^+/+ male mice, but partially in the Tph2^−/− ones. Hence, we suggest that the dose-dependent and long-lasting inhibitory effects of chronic predator exposure on male–male aggression, sexual attractiveness of urine odor, and mRNA expression of central regulatory genes might be mediated through the 5-HT system in the brain of male mice.

Testosterone enhances risk tolerance without altering motor impulsivity in male rats

Anabolic-androgenic steroids (AAS) increase impulsive and uncontrolled aggressive ('roid rage) in humans and enhance agonistic behavior in animals. However, the underlying mechanisms for AAS-induced aggression remain unclear. Potential contributing elements include an increase risk-taking and/or motor impulsivity due to AAS. This study addressed the effects of chronic high-dose testosterone on risk tolerance using a risky decision-making task (RDT) and motor impulsivity with a go/no-go task in operant chambers. Male Long-Evans rats were treated for at least 4 weeks with testosterone (7.5mg/kg) or vehicle beginning in late adolescence. Testosterone was used because it is popular among human AAS users. In RDT testing, one lever was paired with delivery of a small "safe" food reward, while the other was paired with a large "risky" reward associated with an increasing risk of footshock (0%, 25%, 50%, 75%, 100%) in successive test blocks. Three shock intensities were used: 1.0, 1.2, and 1.4mA/kg. As shock intensity and risk of shock increased, preference for the lever signifying a large reward significantly declined for both vehicle- and testosterone-treated rats (p<0.05). There was also a significant effect of drug (p<0.05), where testosterone-treated rats showed greater preference for the large reward, compared to vehicle-treated controls. Increased preference for the large reward, despite risk of footshock, is consistent with increased risk tolerance. In go/no-go testing, rats were trained to press a single lever if the go cue was presented (stimulus light) or to refrain from pressing during the no-go cue (tone). There was no effect of testosterone on pre-cue responses, or performance in go and no-go trials. These results suggest that AAS may increase risk-tolerance without altering motor impulsivity.

Adolescent anabolic/androgenic steroids: Aggression and anxiety during exposure predict behavioral responding during withdrawal in Syrian hamsters (Mesocricetus auratus)

In the U.S. and worldwide anabolic/androgenic steroid use remains high in the adolescent population. This is concerning given that anabolic/androgenic steroid use is associated with a higher incidence of aggressive behavior during exposure and anxiety during withdrawal. This study uses pubertal Syrian hamsters (Mesocricetus auratus) to investigate the hypothesis that an inverse behavioral relationship exists between anabolic/androgenic steroid-induced aggression and anxiety across adolescent exposure and withdrawal. In the first experiment, we examined aggression and anxiety during adolescent anabolic/androgenic steroid exposure and withdrawal. Adolescent anabolic/androgenic steroid administration produced significant increases in aggression and decreases in anxiety during the exposure period followed by significant decreases in aggression and increases in anxiety during anabolic/androgenic steroid withdrawal. In a second experiment, anabolic/androgenic steroid exposed animals were separated into groups based on their aggressive response during the exposure period and then tested for anxiety during exposure and then for both aggression and anxiety during withdrawal. Data were analyzed using a within-subjects repeated measures predictive analysis. Linear regression analysis revealed that the difference in aggressive responding between the anabolic/androgenic steroid exposure and withdrawal periods was a significant predictor of differences in anxiety for both days of testing. Moreover, the combined data suggest that the decrease in aggressive behavior from exposure to withdrawal predicts an increase in anxiety-like responding within these same animals during this time span. Together these findings indicate that early anabolic/androgenic steroid exposure has potent aggression- and anxiety-eliciting effects and that these behavioral changes occur alongside a predictive relationship that exists between these two behaviors over time.

Androgenic anabolic steroid exposure during adolescence: ramifications for brain development and behavior

This article is part of a Special Issue "Puberty and Adolescence". Puberty is a critical period for brain maturation that is highly dependent on gonadal sex hormones. Modifications in the gonadal steroid environment, via the use of anabolic androgenic steroids (AAS), have been shown to affect brain development and behavior. Studies in both humans and animal models indicate that AAS exposure during adolescence alters normal brain remodeling, including structural changes and neurotransmitter function. The most commonly reported behavioral effect is an increase in aggression. Evidence has been presented to identify factors that influence the effect of AAS on the expression of aggression. The chemical composition of the AAS plays a major role in determining whether aggression is displayed, with testosterone being the most effective. The hormonal context, the environmental context, physical provocation and the perceived threat during the social encounter have all been found to influence the expression of aggression and sexual behavior. All of these factors point toward an altered behavioral state that includes an increased readiness to respond to a social encounter with heightened vigilance and enhanced motivation. This AAS-induced state may be defined as emboldenment. The evidence suggests that the use of AAS during this critical period of development may increase the risk for maladaptive behaviors along with neurological disorders.

Serotonin modulates anxiety-like behaviors during withdrawal from adolescent anabolic-androgenic steroid exposure in Syrian hamsters

From the U.S. to Europe and Australia anabolic steroid abuse remains high in the adolescent population. This is concerning given that anabolic steroid use is associated with a higher incidence of pathological anxiety that often appears during withdrawal from use. This study uses pubertal Syrian hamsters (Mesocricetus auratus) to investigate the hypothesis that adolescent anabolic/androgenic steroid (AAS) exposure predisposes hamsters to heightened levels of anxiety during AAS withdrawal that is modulated by serotonin (5HT) neural signaling. In the first two sets of experiments, adolescent AAS-treated hamsters were tested for anxiety 21 days after the cessation of AAS administration (i.e., during AAS withdrawal) using the elevated plus maze (EPM), dark/light (DL), and seed finding (SF) tests and then examined for differences in 5HT afferent innervation to select areas of the brain important for anxiety. In the EPM and DL tests, adolescent AAS exposure leads to significant increases in anxiety-like response during AAS withdrawal. AAS-treated hamsters showed long-term reductions in 5HT innervation within several areas of the hamster brain implicated in anxiety, most notably the anterior hypothalamus and the central and medial amygdala. However, no differences in 5HT were found in other anxiety areas, e.g., frontal cortex and lateral septum. In the last experiment, adolescent AAS-treated hamsters were scored for anxiety on the 21st day of AAS withdrawal following the systemic administration of saline or one of three doses of fluoxetine, a selective serotonin reuptake inhibitor. Saline-treated hamsters showed high levels of AAS withdrawal-induced anxiety, while treatment with fluoxetine reduced AAS withdrawal-induced anxiety. These findings indicate that early AAS exposure has potent anxiogenic effects during AAS withdrawal that are modulated, in part, by 5HT signaling.

The neurobiology of abnormal manifestations of aggression--a review of hypothalamic mechanisms in cats, rodents, and humans

Aggression research was for long dominated by the assumption that aggression-related psychopathologies result from the excessive activation of aggression-promoting brain mechanisms. This assumption was recently challenged by findings with models of aggression that mimic etiological factors of aggression-related psychopathologies. Subjects submitted to such procedures show abnormal attack features (mismatch between provocation and response, disregard of species-specific rules, and insensitivity toward the social signals of opponents). We review here 12 such laboratory models and the available human findings on the neural background of abnormal aggression. We focus on the hypothalamus, a region tightly involved in the execution of attacks. Data show that the hypothalamic mechanisms controlling attacks (general activation levels, local serotonin, vasopressin, substance P, glutamate, GABA, and dopamine neurotransmission) undergo etiological factor-dependent changes. Findings suggest that the emotional component of attacks differentiates two basic types of hypothalamic mechanisms. Aggression associated with increased arousal (emotional/reactive aggression) is paralleled by increased mediobasal hypothalamic activation, increased hypothalamic vasopressinergic, but diminished hypothalamic serotonergic neurotransmission. In aggression models associated with low arousal (unemotional/proactive aggression), the lateral but not the mediobasal hypothalamus is over-activated. In addition, the anti-aggressive effect of serotonergic neurotransmission is lost and paradoxical changes were noticed in vasopressinergic neurotransmission. We conclude that there is no single 'neurobiological road' to abnormal aggression: the neural background shows qualitative, etiological factor-dependent differences. Findings obtained with different models should be viewed as alternative mechanisms rather than conflicting data. The relevance of these findings for understanding and treating of aggression-related psychopathologies is discussed. This article is part of a Special Issue entitled 'Extrasynaptic ionotropic receptors'.

Influence of the single or combined administration of cocaine and testosterone in autonomic and neuroendocrine responses to acute restraint stress

Abuse of cocaine and androgenic-anabolic steroids (AASs) has become a serious public health problem. Despite reports of an increase in the incidence of simultaneous abuse of these substances, potential toxic interactions between cocaine and AASs are poorly known. In the present study, we investigated the effects of either single or combined administration of testosterone and cocaine for one or 10 consecutive days on autonomic (arterial pressure, heart rate and tail cutaneous temperature) and neuroendocrine (plasma corticosterone) responses induced by acute restraint stress in rats. Combined administration of testosterone and cocaine for 10 days reduced the increase in heart rate and plasma corticosterone level, as well as the fall in tail skin temperature induced by restraint stress. Furthermore, repeated administration of cocaine inhibited the increase in arterial pressure observed during restraint, and this effect was not affected by coadministration of testosterone. Ten-day combined administration of testosterone and cocaine increased basal values of arterial pressure. Moreover, chronic administration of testosterone induced rest bradycardia and elevated basal level of plasma corticosterone. One-day single or combined administration of the drugs did not affect any parameter investigated. In conclusion, the present study demonstrated that combined administration of testosterone and cocaine changed the autonomic and neuroendocrine responses to acute restraint stress. These findings suggest that interaction between AASs and cocaine may affect the ability to cope with stressful events.

Testosterone levels in healthy men are related to amygdala reactivity and memory performance

Testosterone is a steroid hormone thought to influence both emotional and cognitive functions. It is unknown, however, if testosterone also affects the interaction between these two domains, such as the emotional arousal-induced enhancement of memory. Healthy subjects (N=234) encoded pictures taken from the International Affective Picture System (IAPS) during functional magnetic resonance imaging (fMRI) and underwent a free recall test 10 min after memory encoding. We show that higher endogenous testosterone levels at encoding were associated with higher arousal ratings of neutral pictures in men. fMRI analysis revealed that higher testosterone levels were related to increased brain activation in the amygdala during encoding of neutral pictures. Moreover, endogenous testosterone levels were positively correlated with the number of freely recalled neutral pictures. No such relations were found in women. These findings point to a male-specific role for testosterone in enhancing memory by increasing the biological salience of incoming information.

Hypothalamic expression of Peg3 gene is associated with maternal care differences between SM/J and LG/J mouse strains

Maternal care is essential in mammals, and variations in the environment provided by mothers may directly influence the viability of newborns and emotional behavior later in life. A previous study investigated genetic variations associated with maternal care in an intercross of LG/J and SM/J inbred mouse strains and identified two single-locus QTLs (quantitative trait loci). Here, we selected three candidate genes located within these QTLs intervals; Oxt on chromosome 2, and FosB and Peg3 on chromosome 7 and tested their association with maternal care. LG/J females showed impaired postpartum nest building and pup retrieval, a one-day delay in milk ejection, reduced exploratory activity, and higher anxiety-like behavior when compared to SM/J females. The nucleotide sequences of Oxt and FosB were similar between strains, as were their hypothalamic expression levels. Conversely, Peg3 nucleotide sequences showed four nonsynonymous replacement substitutions on LG/J dams, T11062G, G13744A, A13808G, and G13813A, and a 30 base pair (10 aa) in tandem repeat in the coding region with three copies in SM/J and five copies in LG/J. Maternal care impaired LG/J mothers express 37% lower Peg3 mRNA levels in the hypothalamus on the second postpartum day. We also found an association of the Peg3 repeat-variant and poor maternal care in F(2) heterozygote females derived from a LG/J × SM/J intercross. These results may suggest that the maternally imprinted Peg3 gene is responsible for the single-locus QTL on chromosome 7 that has been shown to influence maternal care in these strains. Furthermore, these data provide additional support for an epigenetic regulation of maternal behavior.

Corticotropin-releasing factor modulation of forebrain GABAergic transmission has a pivotal role in the expression of anabolic steroid-induced anxiety in the female mouse

Increased anxiety is commonly observed in individuals who illicitly administer anabolic androgenic steroids (AAS). Behavioral effects of steroid abuse have become an increasing concern in adults and adolescents of both sexes. The dorsolateral bed nucleus of the stria terminalis (dlBnST) has a critical role in the expression of diffuse anxiety and is a key site of action for the anxiogenic neuromodulator, corticotropin releasing factor (CRF). Here we demonstrate that chronic, but not acute, exposure of female mice during adolescence to AAS augments anxiety-like behaviors; effects that were blocked by central infusion of the CRF receptor type 1 antagonist, antalarmin. AAS treatment selectively increased action potential (AP) firing in neurons of the central amygdala (CeA) that project to the dlBnST, increased the frequency of GABA(A) receptor-mediated spontaneous inhibitory postsynaptic currents (sIPSCs) in dlBnST target neurons, and decreased both c-FOS immunoreactivity (IR) and AP frequency in these postsynaptic cells. Acute application of antalarmin abrogated the enhancement of GABAergic inhibition induced by chronic AAS exposure whereas application of CRF to brain slices of naïve mice mimicked the actions of this treatment. These results, in concert with previous data demonstrating that chronic AAS treatment results in enhanced levels of CRF mRNA in the CeA and increased CRF-IR in the dlBnST neuropil, are consistent with a mechanism in which the enhanced anxiety elicited by chronic AAS exposure involves augmented inhibitory activity of CeA afferents to the dlBnST and CRF-dependent enhancement of GABAergic inhibition in this brain region.

The Sturm und Drang of anabolic steroid use: angst, anxiety, and aggression

Anabolic androgenic steroids (AAS) are illicitly administered to enhance athletic performance and body image. Although conferring positive actions on performance, steroid abuse is associated with changes in anxiety and aggression. AAS users are often keenly invested in understanding the biological actions of these drugs. Thus, mechanistic information on AAS actions is important not only for the biomedical community, but also for steroid users. Here we review findings from animal studies on the impact of AAS exposure on neural systems that are crucial for the production of anxiety and aggression, and compare the effects of the different classes of AAS and their potential signaling mechanisms, as well as context-, age- and sex-dependent aspects of their actions.