Attenuating effects of testosterone on depressive-like behavior in the forced swim test in healthy male rats

It is all About the Chase: Neurosteroidogenesis in Male Rats is Driven by Control of Mating Pace

BACKGROUND

Masculine sexual behaviors are dependent on androstane-derived steroids; however, the modulatory effects of mating, and of mating control, on androstane neurosteroidogenesis remain largely unknown.

OBJECTIVE

Herein, we investigated the effects of mating control, prior sexual experience, and age on brain region specific neurosteroidogenic responses in male rats.

METHODS

Effects of acute sexual experience were tested in naïve male rats that either remained sexually- naïve, were exposed to a standard mating chamber, or were either given control of the mating pace in a standard mating chamber (male control) or mated wherein the female stimulus rat controlled the mating pace in a paced-mating chamber (female control). Aged (10-12 months) sexually responsive male rats were similarly euthanized from the homecage or engaged in male controlled or female controlled mating. All rats were euthanized immediately following exposure conditions for radioimmunoassay of steroids in midbrain, hypothalamus, hippocampus and cortex.

RESULTS

Consummatory sexual behavior in male vs. female-controlled mating paradigms was altered by age and prior sexual experience. Male-controlled mating increased androstane neurosteroid metabolism, such that complementary increases in the testosterone (T) metabolite 5α-androstane-3α-17β- diol (3α-diol) in the midbrain and hypothalamus of male rats corresponded to decreases in the prohormone, T. 3α-diol were increased in the hippocampus in response to the context alone, and to a lesser degree in response to mating. Mating diminished neurosteroidogenesis in the cortex. Neurosteroidogenesis was overall reduced in aged male rats compared to naïve controls, however, these effects were more prominent in sexually non-responsive aged male rats.

CONCLUSION

Extending previous findings, these results indicate differential production of androstane neurosteroids in a mating exposure, age and brain region dependent manner.

Febrile Seizures Cause Depression and Anxiogenic Behaviors in Rats

Febrile seizure (FS) is a common type of seizure occurring in human during infancy and childhood. Although an epileptic seizure is associated with psychiatric disorders and comorbid diseases such as depression, anxiety, autism spectrum disorders, sleep disorders, attention deficits, cognitive impairment, and migraine, the causal relationship between FS and psychiatric disorders is poorly understood. The objective of the current study was to investigate the relationship of FS occurrence in childhood with the pathogenesis of anxiety disorder and depression using an FS rat model. We induced febrile seizures in infantile rats (11 days postnatal) using a mercury vapor lamp. At 3 weeks and 12 weeks after FS induction, we examined behaviors and recorded local field potentials (LFPs) to assess anxiety and depression disorder. Interestingly, after FS induction in infantile rats, anxiogenic behaviors and depression-like phenotypes were found in both adult and juvenile FS rats. The analysis of LFPs revealed that 4-7 Hz hippocampal theta rhythm, a neural oscillatory marker for anxiety disorder, was significantly increased in FS rats compared with their wild-type littermates. Taken together, our findings suggest that FS occurrence in infants is causally related to increased levels of anxiety-related behaviors and depression-like symptoms in juvenile and adult rodents.

Testosterone Supplementation Induces Age-Dependent Augmentation of the Hypoxic Ventilatory Response in Male Rats With Contributions From the Carotid Bodies

Excessive carotid body responsiveness to O₂ and/or CO₂/H⁺ stimuli contributes to respiratory instability and apneas during sleep. In hypogonadal men, testosterone supplementation may increase the risk of sleep-disordered breathing; however, the site of action is unknown. The present study tested the hypothesis that testosterone supplementation potentiates carotid body responsiveness to hypoxia in adult male rats. Because testosterone levels decline with age, we also determined whether these effects were age-dependent. In situ hybridization determined that androgen receptor mRNA was present in the carotid bodies and caudal nucleus of the solitary tract of adult (69 days old) and aging (193–206 days old) male rats. In urethane-anesthetized rats injected with testosterone propionate (2 mg/kg; i.p.), peak breathing frequency measured during hypoxia (FiO₂ = 0.12) was 11% greater vs. the vehicle treatment group. Interestingly, response intensity following testosterone treatment was positively correlated with animal age. Exposing ex vivo carotid body preparations from young and aging rats to testosterone (5 nM, free testosterone) 90–120 min prior to testing showed that the carotid sinus nerve firing rate during hypoxia (5% CO₂ + 95% N₂; 15 min) was augmented in both age groups as compared to vehicle (<0.001% DMSO). Ventilatory measurements performed using whole body plethysmography revealed that testosterone supplementation (2 mg/kg; i.p.) 2 h prior reduced apnea frequency during sleep. We conclude that in healthy rats, age-dependent potentiation of the carotid body’s response to hypoxia by acute testosterone supplementation does not favor the occurrence of apneas but rather appears to stabilize breathing during sleep.

Sex Differences in Affective Dysfunction and Alterations in Parvalbumin in Rodent Models of Early Life Adversity

The early life environment markedly influences brain and behavioral development, with adverse experiences associated with increased risk of anxiety and depressive phenotypes, particularly in females. Indeed, early life adversity (ELA) in humans (i.e., caregiver deprivation, maltreatment) and rodents (i.e., maternal separation, resource scarcity) is associated with sex-specific emergence of anxious and depressive behaviors. Although these disorders show clear sex differences in humans, little attention has been paid toward evaluating sex as a biological variable in models of affective dysfunction; however, recent rodent work suggests sex-specific effects. Two widely used rodent models of ELA approximate caregiver deprivation (i.e., maternal separation) and resource scarcity (i.e., limited bedding). While these approaches model aspects of ELA experienced in humans, they span different portions of the pre-weaning developmental period and may therefore differentially contribute to underlying mechanistic risk. This is borne out in the literature, where evidence suggests differences in trajectories of behavior depending on the type of ELA and/or sex; however, the neural underpinning of these differences is not well understood. Because anxiety and depression are thought to involve dysregulation in the balance of excitatory and inhibitory signaling in ELA-vulnerable brain regions (e.g., prefrontal cortex, amygdala, hippocampus), outcomes are likely driven by alterations in local and/or circuit-specific inhibitory activity. The most abundant GABAergic subtypes in the brain, accounting for approximately 40% of inhibitory neurons, contain the calcium-binding protein Parvalbumin (PV). As PV-expressing neurons have perisomatic and proximal dendritic targets on pyramidal neurons, they are well-positioned to regulate excitatory/inhibitory balance. Recent evidence suggests that PV outcomes following ELA are sex, age, and region-specific and may be influenced by the type and timing of ELA. Here, we suggest the possibility of a combined role of PV and sex hormones driving differences in behavioral outcomes associated with affective dysfunction following ELA. This review evaluates the literature across models of ELA to characterize neural (PV) and behavioral (anxiety- and depressive-like) outcomes as a function of sex and age. Additionally, we detail a putative mechanistic role of PV on ELA-related outcomes and discuss evidence suggesting hormone influences on PV expression/function which may help to explain sex differences in ELA outcomes.

Altered Emotional Phenotypes in Chronic Kidney Disease Following 5/6 Nephrectomy

Increased prevalence of chronic kidney disease (CKD) and neurological disorders including cerebrovascular disease, cognitive impairment, peripheral neuropathy, and dysfunction of central nervous system have been reported during the natural history of CKD. Psychological distress and depression are serious concerns in patients with CKD. However, the relevance of CKD due to decline in renal function and the pathophysiology of emotional deterioration is not clear. Male Sprague Dawley rats were divided into three groups: sham control, 5/6 nephrectomy at 4 weeks, and 5/6 nephrectomy at 10 weeks. Behavior tests, local field potentials, and histology and laboratory tests were conducted and investigated. We provided direct evidence showing that CKD rat models exhibited anxiogenic behaviors and depression-like phenotypes, along with altered hippocampal neural oscillations at 1–12 Hz. We generated CKD rat models by performing 5/6 nephrectomy, and identified higher level of serum creatinine and blood urea nitrogen (BUN) in CKD rats than in wild-type, depending on time. In addition, the level of α-smooth muscle actin (α-SMA) and collagen I for renal tissue was markedly elevated, with worsening fibrosis due to renal failures. The level of anxiety and depression-like behaviors increased in the 10-week CKD rat models compared with the 4-week rat models. In the recording of local field potentials, the power of delta (1–4 Hz), theta (4–7 Hz), and alpha rhythm (7–12 Hz) was significantly increased in the hippocampus of CKD rats compared with wild-type rats. Together, our findings indicated that anxiogenic behaviors and depression can be induced by CKD, and these abnormal symptoms can be worsened as the onset of CKD was prolonged. In conclusion, our results show that the hippocampus is vulnerable to uremia.

Sexual Motivation and Sexual Reward in Male Rats are Attenuated by the Gonadotropin-Releasing Hormone Receptor Antagonist Degarelix

BACKGROUND

Preclinical studies that have examined the effects of androgen deprivation therapies (ADTs) on sexual outcomes have either relied on a surgical castration model of ADTs or have largely focused on consummatory sexual behaviors.

AIM

The aim of this study was to examine the effects of a single administration of the gonadotropin-releasing hormone receptor antagonist, degarelix, on sexual incentive motivation (SIM), sexual reward, consummatory sexual behaviors, anxiety-like behavior, and androgen receptor signaling in male rats, and to determine if sexual stimulation attenuates the effects of degarelix on SIM.

METHODS

Male rats were treated with degarelix, or vehicle, and half of the rats in each condition were briefly exposed to a sexually receptive female immediately before SIM trials (experiment 1). Rats treated with degarelix or vehicle were also given a sex-conditioned place preference test (experiment 2A), weekly mating tests (experiment 2B), and an elevated zero maze test (experiment 3). Androgen-sensitive tissues were excised upon completion of testing.

OUTCOMES

SIM was indicated by the percentage of time spent near a sexually receptive female on the SIM tests. The percentage of time spent in the chamber of a conditioned place preference maze associated with sexual experience was indicative of sexual reward. The percentage of trials in which a mount, intromission, and ejaculation occurred was indicative of copulatory ability. Sexual performance was characterized by the average latencies to first exhibit these behaviors, as well as the average frequency of these behaviors. Anxiety-like behavior was indicated by the percentage of time in the open zones of an elevated zero maze. Relative weights of the seminal vesicles and bulbourethral glands were used to quantify androgen activity.

RESULTS

Rats treated with degarelix exhibited lower levels of SIM. In rats treated with degarelix, contact with a female immediately before SIM testing increased activity, but not SIM. Treatment with degarelix reduced the rewarding aspects of sexual behavior, as well as most aspects of copulatory ability and sexual performance. Degarelix treatment reduced androgen signaling, but did not impact anxiety-like behavior.

CLINICAL IMPLICATIONS

The behavioral side effects associated with the use of degarelix may be restricted to sexual behaviors.

STRENGTHS & LIMITATIONS

Strengths include the objective measurement of sexual behaviors. The study is limited in that only one ADT was examined.

CONCLUSION

These findings serve as an extension of previous preclinical studies as they indicate that gonadotropin-releasing hormone receptor antagonism in male rats also attenuates sexual motivation and sexual reward, in addition to copulatory ability and sexual performance. Hawley WR, Kapp LE, Green PA, et al. Sexual Motivation and Reward in Male Rats are Attenuated by the Gonadotropin-Releasing Hormone Receptor Antagonist Degarelix. J Sex Med 2021;18:240-255.

Associations between sex hormones, sleep problems and depression: A systematic review

Sleep problems and depression are both common and have a high impact on quality of life. They are also strongly associated and commonly occur together. During the reproductive age, both sleep problems and depression are almost twice as common in women than men. Epidemiological studies show that women experience more sleep problems and depressive symptoms around times when sex hormones change, such as puberty and menopause, but it is unclear what effect sex hormones have on sleep problems and depression. This systematic review aims to summarize and evaluate studies that investigated the relationship between sex hormones, sleep and depression. Systematic search resulted in 2895 articles, of which 13 met inclusion criteria. Depressed patients showed worse sleep than controls, but no significant difference in endogenous hormone levels was found. Additionally, higher endogenous estrogen was associated with better sleep in controls, but associations between endogenous sex hormones and depressive symptoms were inconclusive. More research on the effect of sex hormones on sleep and depression is necessary.

Behavioral and hormonal effects of prolonged Sildenafil treatment in a mouse model of chronic social stress

Chronic social defeat can inhibit the reproductive system of subordinate males and causes behavioral deficits. Sildenafil treatment increases mice testosterone levels through its effects on Leydig cells of mice and it has been found to work as an antidepressant drug both in humans and in animal models. Since previous findings showed that sildenafil can counteract the inhibitory effects of chronic social defeat on agonistic, reproductive and anxiety-like behaviors of subordinate male mice, we investigated whether these behavioral outcomes can be explained by Sildenafil stimulation of testosterone. CD1 mice underwent an intruder-resident paradigm. After the fifth day of test, subordinate mice were injected with either a 10 mg/kg Sildenafil or a saline solution for 4 weeks. The results of the present study showed that Sildenafil treatment increased counterattacking behaviors and sexual motivation of subordinate males in addition to limiting the increase in body weight often observed in subordinate mice following chronic psychosocial stress. Moreover, sildenafil treated mice showed a pattern of behaviors reflecting lower anxiety. In agreement with previous studies, Sildenafil also increased testosterone levels. These data demonstrate that sildenafil can counteract the effects of chronic stress, possibly through its stimulatory effects on Leydig cells. These data demonstrate that sildenafil might counteract the effects of chronic psychosocial stress through centrally and peripherally mediated mechanisms.

The age-dependent effect of pre-pubertal castration on anxiety-like behaviour in male rats

Adolescence is considered to be a critical period of sex hormone action (re)organising the brain and determining the behavioural phenotype. Such organisational effects in the brain might be the cause of sex differences in some behavioural features. In this experiment, we aimed to examine the role of pubertal sex hormones in development of anxiety in male rats. Male rats underwent gonadectomy prior to puberty onset, and were tested for explorative and anxiety-like behaviour in adolescence as well as in young adulthood. In adolescence, but not in adulthood, gonadectomised rats spend by 50% more time (p < .05) in the centre zone of the open-field than sham-operated counterparts. Young adult gonadectomised rats showed approximately 1.5-fold greater exploratory activity, in both open field (p < .001) and elevated plus maze (p < .01), in comparison with young adult control rats. Our results indicate that pre-pubertal castration may have test-specific anxiolytic effect in adolescent male rats, and it may attenuate the decline in explorative behaviour in young adult males. These differences in short- and long-term effects of gonadectomy could explain some contradictory results of previous studies on the role of testosterone in anxiety-like behaviour of male rodents. Thus, the age-specific consequences of pre-pubertal hormone deprivation should be considered.

Investigating hormone-induced changes in affective state using the affective bias test in male and female rats

Recent clinical and pre-clinical research suggests that affective biases may play an important role in the development and perpetuation of mood disorders. Studies in animals have also revealed that similar neuropsychological processes can be measured in non-human species using behavioural assays designed to measure biases in learning and memory or decision-making. Given the proposed links between hormones and mood, we used the affective bias test to investigate the effects of different hormone treatments in both male and female rats. Animals were pre-treated with acute doses of hormone or vehicle control prior to learning each of two independent substrate-reward associations. During a subsequent choice test, positive or negative biases were observed by animal's preference towards or away from the substrate learnt during drug treatment respectively. In both sexes, oestradiol and the oestrogen-like compound bisphenol A induced positive biases, whilst blockade of oestrogen hormones with formestane induced a negative bias. Progesterone induced a negative bias in both sexes, but testosterone only induced a negative bias in males. Blocking testosterone with flutamide induced a positive bias in both sexes at the higher dose (10 mg/kg). The oxytocin analogue, carbetocin induced positive biases in both sexes but the vasopressin analogue, desmopressin, induced a positive bias in male rats only. These results provide evidence that modulating levels of hormones using exogenous treatments can induce affective biases in rats. They also suggest that hormone-induced affective biases influence cognitive and emotional behaviour and could have longer-term effects in some mood disorders.

Neurobiological mechanisms underlying sex-related differences in stress-related disorders: Effects of neuroactive steroids on the hippocampus

Men and women differ in their vulnerability to a variety of stress-related illnesses, but the underlying neurobiological mechanisms are not well understood. This is likely due to a comparative dearth of neurobiological studies that assess male and female rodents at the same time, while human neuroimaging studies often don't model sex as a variable of interest. These sex differences are often attributed to the actions of sex hormones, i.e. estrogens, progestogens and androgens. In this review, we summarize the results on sex hormone actions in the hippocampus and seek to bridge the gap between animal models and findings in humans. However, while effects of sex hormones on the hippocampus are largely consistent in animals and humans, methodological differences challenge the comparability of animal and human studies on stress effects. We summarise our current understanding of the neurobiological mechanisms that underlie sex-related differences in behavior and discuss implications for stress-related illnesses.

On the Role of Testosterone in Anxiety-Like Behavior Across Life in Experimental Rodents

Testosterone affects brain functions and might explain some of the observed behavioral sex differences. Animal models may help in elucidating the possible involvement of sex hormones in these sex differences. The effects of testosterone have been intensively investigated, especially in anxiety models. Numerous experiments have brought inconsistent results with either anxiolytic or anxiogenic effects. Besides methodological variations, contradictory findings might be explained by the divergent metabolism of testosterone and its recognition by neurons during prenatal and postnatal development. Gonadectomy and subsequent supplementation have been used to study the role of sex hormones. However, the variable duration of hypogonadism might affect the outcomes and the effect of long-term androgen deficiency is understudied. Testosterone can be metabolized to dihydrotestosterone strengthening the androgen signaling, but also to estradiol converting the androgen to estrogen activity. Moreover, some metabolites of testosterone can modulate γ-aminobutyric acid and serotonergic neurotransmission. Here we review the currently available experimental data in experimental rodents on the effects of testosterone on anxiety during development. Based on the experimental results, females are generally less anxious than males from puberty to middle-age. The anxiety-like behavior of females and males is likely influenced by early organizational effects, but might be modified by activational effects of testosterone and its metabolites. The effects of sex hormones leading to anxiogenesis or anxiolysis depend on factors affecting hormonal status including age. The biological and several technical issues make the study of effects of testosterone on anxiety very complex and should be taken into account when interpreting experimental results.

Increased estrogen level can be associated with depression in males

BACKGROUND

Several studies have shown a positive association between depression and obesity; however the underlying mechanisms are not fully understood. It is not known if this association is driven by altered sex hormone levels in men due to increased BMI.

PATIENTS AND METHODS

Data were obtained from the LIFE-Adult-Study, a population-based cohort study. A total of 3925 men (2244<60years and 1681>60years) were included into analyses. Associations between BMI, sex hormones and depressive symptomatology according to CES-D score were evaluated.

RESULTS

Obese men had compared to normal weight controls lower total testosterone (12.6±4.7 vs 19.4±5.5 nmol/L, p<0.001 in <60years, and 13.8±6.9 vs 18.3±5.9 nmol/L, p<0.001 in >60years group) and free testosterone (249.0±73.9 vs 337.2±82.0pmol/L, p<0.001, and 217.8±71.2 vs 263.4±72.2pmol/L, p<0.001), and increased estradiol in older group only (97.3±43.0 vs 82.3±34.2pmol/L, p<0.001 in obese). Men <60years old with depressive symptomatology had higher estradiol levels compared to those without depressive symptomatology (96.3±40.7 vs 84.4±36.6pmol/L, p<0.001), however no association with BMI was observed.

CONCLUSIONS

Selected sex hormone parameters were significantly different in overweight and obese compared to normal weight males and certain differences could be seen between younger and older males. Depressive symptomatology was associated with increased estradiol levels in younger men, regardless of BMI.

The role of neuropeptide-Y in nandrolone decanoate-induced attenuation of antidepressant effect of exercise

Since the increased prevalence of anabolic androgenic steroids abuse in last few decades is usually accompanied by various exercise protocols, the scope of our study was to evaluate the effects of chronic nandrolone decanoate administration in supraphysiological dose and a prolonged swimming protocol (alone and simultaneously with nandrolone decanoate) on depressive state in male rats. Simultaneously, we investigated the possible alterations in neuropeptide Y (NPY) content in blood and the hippocampus, in order to determine the role of NPY in the modulation of depressive-like behavior.Exercise induced antidepressant effects in tail suspension test (decrease of the total duration of immobility), as well as significant increase in the number of hippocampal NPY-interneurons in CA1 region. Chronic nandrolone decanoate treatment attenuated the beneficial antidepressant effects of exercise as measured by the tail suspension test parameters. Simultaneously, nandrolone decanoate treatment resulted in diminution of NPY content both in blood (decreased serum levels) and in hippocampus (the significant decrease in NPY expression in all three investigated hippocampal regions-CA1, CA2/3 and DG). Our findings indicate that alterations in serum and hippocampal NPY contents may underlie the changes in depressive state in rats. The exercise was beneficial as it exerted antidepressant effect, while chronic nandrolone decanoate treatment resulted in depressive-like behavior. Furthermore, the behavioral indicators of depression showed strong correlations with the serum levels and the hippocampal content of NPY.

Animal models to improve our understanding and treatment of suicidal behavior

Worldwide, suicide is a leading cause of death. Although a sizable proportion of deaths by suicide may be preventable, it is well documented that despite major governmental and international investments in research, education and clinical practice suicide rates have not diminished and are even increasing among several at-risk populations. Although nonhuman animals do not engage in suicidal behavior amenable to translational studies, we argue that animal model systems are necessary to investigate candidate endophenotypes of suicidal behavior and the neurobiology underlying these endophenotypes. Animal models are similarly a critical resource to help delineate treatment targets and pharmacological means to improve our ability to manage the risk of suicide. In particular, certain pathophysiological pathways to suicidal behavior, including stress and hypothalamic-pituitary-adrenal axis dysfunction, neurotransmitter system abnormalities, endocrine and neuroimmune changes, aggression, impulsivity and decision-making deficits, as well as the role of critical interactions between genetic and epigenetic factors, development and environmental risk factors can be modeled in laboratory animals. We broadly describe human biological findings, as well as protective effects of medications such as lithium, clozapine, and ketamine associated with modifying risk of engaging in suicidal behavior that are readily translatable to animal models. Endophenotypes of suicidal behavior, studied in animal models, are further useful for moving observed associations with harmful environmental factors (for example, childhood adversity, mechanical trauma aeroallergens, pathogens, inflammation triggers) from association to causation, and developing preventative strategies. Further study in animals will contribute to a more informed, comprehensive, accelerated and ultimately impactful suicide research portfolio.

Behavioral effects of Citrus limon and Punica granatum combinations in rats

Dietary supplements are becoming more influential as viable treatment for common chronic diseases and to promote normal development and functions of all system including brain. Disorders like anxiety and depression may be managed through healthier variations is dietary pattern, since there are indications that diet rich in antioxidants and vitamins diminish anxiety and depression. Hence this investigation was planned to assess the behavioral effects of Citrus limon and Punica granatum in two combination doses i.e. 0.4 + 5 ml/kg and 0.2 + 8 ml/kg C. limon and P. granatum respectively in rats. Antidepressant and anxiolytic effects were explicitly judged twice during 15 days using forced swimming and open field tests and elevated plus maze. In open field test C. limon and P. granatum showed increase in distance travelled, number of central entries and number of rearing's at 0.4 + 5 ml/kg combination, in the elevated plus maze, number of open arm entries were found to be augmented and in forced swimming test, there was decline in duration of immobility and rise in duration of climbing at both combinations i.e. 0.4 + 5 ml/kg and 0.2 + 8 ml/kg C. limon and P. granatum. These results suggest that C. limon and P. granatum at 0.4 + 5 ml/kg combination have anxiolytic and antidepressant effect.

Effects of two-year testosterone replacement therapy on cognition, emotions and quality of life in young and middle-aged hypogonadal men

The aim of the study was to examine the effects of two-year testosterone replacement therapy on cognitive functioning, emotional state and quality of life in young and middle-aged men with hypogonadotropic hypogonadism. Nineteen males diagnosed with hypogonadotropic hypogonadism participated in the study. Cognitive functions were assessed by Trail Making Test and Digit Span Test of Wechsler Adult Intelligence Scale. Emotional state was evaluated by Profile of Mood States. Quality of life was evaluated by WHO Brief Quality of Life Questionnaire. Changes after two-year testosterone replacement therapy were detected in Trail Making A (42.9 ± 22.3 vs. 36.2 ± 22.5, p = .050) and B (90.6 ± 55.3 vs. 65.6 ± 21.4, p = .025) tests, showing improvement in attention and visual scanning abilities, executive function and psychomotor speed, as well as in Digit Span Test forward score (5.4 ± 2.0 vs. 6.1 ± 2.6, p = .046), showing improvement in attention capacity and psychomotor speed. No significant differences were observed in emotional state and quality of life. In conclusion, beneficial effect in cognitive functioning (improved attention and visual scanning ability, executive function and psychomotor speed), but not in emotional state and quality of life, was observed in young and middle-aged hypogonadal men after two-year testosterone replacement therapy.

Behavioral effects of Citrus paradisi in rats

Anxiety and depression adversely affect behavior though these conditions may be handled through environmental and dietary changes. Diet rich in flavonoids and vitamins may support reducing anxiety and depression. Depression is most common but serious illness making life miserable; however the usage of dietary and herbal complements to treat anxiety and depression had been grown by the time. The purpose of this investigation was to characterize the behavioral properties of Citrus paradisi in rats at diverse doses i.e. 0.1, 0.3 and 0.5 ml/kg. Anxiolytic and antidepressant actions were particularly measured twice in 15 days through elevated plus maze, open field and forced swimming tests. C. paradisi, revealed increase in the locomotor activity and the exploratory skills of the animals, as assessed in the open-field. Indeed C. paradisi had a strong anxiolytic effect in elevated plus-maze, as assessed by an augmented number of entries and the proportion of time spent in the open arms. Moreover there was decline in duration of immobility and rise in duration of climbing during forced swimming test. At the tested doses these results suggest that C. paradisi have the potential to exert a range of CNS-mediated biological activities and thus encourage more investigations in this field.

Sex hormones and adult hippocampal neurogenesis: Regulation, implications, and potential mechanisms

Neurogenesis within the adult hippocampus is modulated by endogenous and exogenous factors. Here, we review the role of sex hormones in the regulation of adult hippocampal neurogenesis in males and females. The review is framed around the potential functional implications of sex hormone regulation of adult hippocampal neurogenesis, with a focus on cognitive function and mood regulation, which may be related to sex differences in incidence and severity of dementia and depression. We present findings from preclinical studies of endogenous fluctuations in sex hormones relating to reproductive function and ageing, and from studies of exogenous hormone manipulations. In addition, we discuss the modulating roles of sex, age, and reproductive history on the relationship between sex hormones and neurogenesis. Because sex hormones have diverse targets in the central nervous system, we overview potential mechanisms through which sex hormones may influence hippocampal neurogenesis. Lastly, we advocate for a more systematic consideration of sex and sex hormones in studying the functional implications of adult hippocampal neurogenesis.

Testosterone has antidepressant-like efficacy and facilitates imipramine-induced neuroplasticity in male rats exposed to chronic unpredictable stress

Hypogonadal men are more likely to develop depression, while testosterone supplementation shows antidepressant-like effects in hypogonadal men and facilitates antidepressant efficacy. Depression is associated with hypothalamic-pituitary-adrenal (HPA) axis hyperactivity and testosterone exerts suppressive effects on the HPA axis. The hippocampus also plays a role in the feedback regulation of the HPA axis, and depressed patients show reduced hippocampal neuroplasticity. We assessed the antidepressant-like effects of testosterone with, or without, imipramine on behavioral and neural endophenotypes of depression in a chronic unpredictable stress (CUS) model of depression. A 21-day CUS protocol was used on gonadectomized male Sprague-Dawley rats treated with vehicle, 1mg of testosterone propionate, 10mg/kg of imipramine, or testosterone and imipramine in tandem. Testosterone treatment reduced novelty-induced hypophagia following CUS exposure, but not under non-stress conditions, representing state-dependent effects. Further, testosterone increased the latency to immobility in the forced swim test (FST), reduced basal corticosterone, and reduced adrenal mass in CUS-exposed rats. Testosterone also facilitated the effects of imipramine by reducing the latency to immobility in the FST and increasing sucrose preference. Testosterone treatment had no significant effect on neurogenesis, though the combination of testosterone and imipramine increased PSA-NCAM expression in the ventral dentate gyrus. These findings demonstrate the antidepressant- and anxiolytic-like effects of testosterone within a CUS model of depression, and provide insight into the mechanism of action, which appears to be independent of enhanced hippocampal neurogenesis.

Minocycline Attenuates Depressive-Like Behaviour Induced by Rat Model of Testicular Torsion: Involvement of Nitric Oxide Pathway

Testicular torsion/detorsion (T/D) can induce depression in pre- and post-pubertal patients. This study was conducted to investigate the psychological impact of testicular torsion and mechanism underlying its depressive-like behaviour, as well as antidepressant-like activity of minocycline and possible involvement of nitric oxide (NO)/cyclic GMP pathway in this paradigm in male rats undergoing testicular T/D. Unilateral T/D was performed in 36 male adult Wistar rats, and different doses of minocycline were injected alone or combined with N(ω) -nitro-l-arginine methyl ester (l-NAME), non-specific NO synthase (NOS) inhibitor; aminoguanidine (AG), specific inducible NOS inhibitor; l-arginine, an NO precursor; and selective PDE5I, sildenafil. After assessment of locomotor activity in open-field test, immobility times were recorded in the forced swimming test (FST). Moreover, 30 days after testicular T/D, testicular venous testosterone and serum nitrite concentrations were measured. A correlation was observed between either a decrease in plasma testosterone or an increase in serum nitrite concentrations with prolongation in immobility time in the testicular T/D-operated rats FST. Minocycline (160 mg/kg) exerted the highest significant antidepressant-like effect in the operated rats in the FST (p < 0.001). Furthermore, combination of subeffective doses of minocycline (80 mg/kg) and either l-NAME (10 mg/kg) or AG (50 mg/kg) demonstrated a significant robust antidepressant-like activity in T/D group (p < 0.01). Consequently, NO/cGMP pathway was involved in testicular T/D-induced depressive-like behaviour and antidepressant-like activity of minocycline in the animal model. Moreover, a contribution was observed between either decreased testosterone or elevated serum nitrite levels and depressive-like behaviour following testicular T/D.

The potential role of exercise in neuro-oncology

Patients with brain and other central nervous system cancers experience debilitating physical, cognitive, and emotional effects, which significantly compromise quality of life. Few efficacious pharmacological strategies or supportive care interventions exist to ameliorate these sequelae and patients report high levels of unmet needs in these areas. There is strong theoretical rationale to suggest exercise may be an effective intervention to aid in the management of neuro-oncological disorders. Clinical research has established the efficacy of appropriate exercise in counteracting physical impairments such as fatigue and functional decline, cognitive impairment, as well as psychological effects including depression and anxiety. While there is promise for exercise to enhance physical and psychosocial wellbeing of patients diagnosed with neurologic malignancies, these patients have unique needs and research is urgently required to explore optimal exercise prescription specific to these patients to maximize safety and efficacy. This perspective article is a discussion of potential rehabilitative effects of targeted exercise programs for patients with brain and other central nervous system cancers and highlights future research directions.

Behavioral effects of Citrus limon in rats

Anxiety and depression are increasing worldwide, however these disorders may be managed by making healthier changes is dietary pattern, since there are evidences that diet rich in antioxidants and vitamins help reduce anxiety and depression. Hence present study was designed to evaluate the behavioral effects of Citrus limon in rats at three different doses i.e. 0.2, 0.4 and 0.6 ml/kg considered as low, moderate and high doses. Anxiolytic and antidepressant activities were specifically assessed twice during 15 days using open field test, elevated plus maze and forced swimming test. In open field test C. limon, revealed increase in distance travelled, number of central entries and number of rearing's at moderate dose, while in the elevated plus maze, number of open arm entries were found to be increased. Whereas in forced swimming test, there was decrease in duration of immobility and increase in duration of climbing. Thus results of present study suggest that C. limon at moderate dose have anxiolytic effect.

Effects of testosterone and estradiol on anxiety and depressive-like behavior via a non-genomic pathway

Besides their known slow genomic effects, testosterone and estradiol have rapid effects in the brain. However, their impact on mood-related behavior is not clear. The aim of this study was to investigate the non-genomic pathway of testosterone and estradiol in the amygdala in relation to anxiety and depressive-like behavior. Sham-operated and gonadectomized male rats (GDX) supplemented with testosterone propionate, estradiol, or olive oil were used. Five minutes after administration, anxiety and depression-like behavior were tested. Estradiol increased anxiolytic behavior in the open-field test compared to the GDX group, but administration of testosterone had no significant effect. Besides, c-Fos expression in the medial nucleus of the amygdala significantly increased after testosterone treatment compared to the GDX group, while no significant difference was observed in the central and the basolateral nuclei of the amygdala in the testosterone-treated group compared to the GDX group. In conclusion, estradiol had an anxiolytic effect via a rapid pathway, but no rapid effect of testosterone on anxiety was found. Further studies elucidating whether the rapid effect is mediated by a non-genomic pathway are needed.

On the effects of testosterone on brain behavioral functions

Testosterone influences the brain via organizational and activational effects. Numerous relevant studies on rodents and a few on humans focusing on specific behavioral and cognitive parameters have been published. The results are, unfortunately, controversial and puzzling. Dosing, timing, even the application route seem to considerably affect the outcomes. In addition, the methods used for the assessment of psychometric parameters are a bit less than ideal regarding their validity and reproducibility. Metabolism of testosterone contributes to the complexity of its actions. Reduction to dihydrotestosterone by 5-alpha reductase increases the androgen activity; conversion to estradiol by aromatase converts the androgen to estrogen activity. Recently, the non-genomic effects of testosterone on behavior bypassing the nuclear receptors have attracted the interest of researchers. This review tries to summarize the current understanding of the complexity of the effects of testosterone on brain with special focus on their role in the known sex differences.

Hormonal changes and increased anxiety-like behavior in a perimenopause-animal model induced by 4-vinylcyclohexene diepoxide (VCD) in female rats

Perimenopause, a transition period that precedes menopause, is characterized by neuroendocrine, metabolic and behavioral changes, and is associated with increased vulnerability to affective disorders. The decrease in ovarian follicles during perimenopause contributes to a dynamic and complex hormonal milieu that is not yet well characterized. In rodents, 4-vinylcyclohexene diepoxide (VCD) induces a gradual depletion of ovarian follicles, modeling the transition to menopause in women. This study was aimed to investigate, in VCD-treated rats, the hormonal status and the behavior in the elevated plus-maze (EPM), a widely used test to assess anxiety-like behavior. From the postnatal day 28, rats were treated with VCD or vehicle for 15 days. At 80±5 days after the beginning of treatment the experiments were performed at proestrus and diestrus. In the first experiment rats were decapitated, ovary was collected and blood samples were taken for estradiol, progesterone, follicle stimulant hormone (FSH), testosterone, dihydrotestosterone (DHT) and corticosterone measurements. In the second experiment, rats were subjected to the EPM for 5 min, and behavioral categories recorded. Administration of VCD induced follicular depletion as well as an increase of the number of atretic follicles demonstrating the treatment efficacy. The transitional follicular depletion was accompanied by lower progesterone, testosterone and DHT with no changes in the FSH, estradiol and corticosterone plasma levels. On the EPM, rats showed decreased open arm exploration and increased risk assessment behavior, indicating increased anxiety. These findings show that administration of VCD to induce ovarian failure results in endocrine and anxiety-related changes that are similar to the symptoms exhibited by women during menopause transition. Thus, this model seems to be promising in the study of perimenopause-related changes.

Sex differences in anxiety and depression: role of testosterone

Compelling evidence exists for pervasive sex differences in pathological conditions, including anxiety and depressive disorders, with females more than twice as likely to be afflicted. Gonadal hormones may be a major factor in this disparity, given that women are more likely to experience mood disturbances during times of hormonal flux, and testosterone may have protective benefits against anxiety and depression. In this review we focus on the effects of testosterone in males and females, revealed in both human and animal studies. We also present possible neurobiological mechanisms underlying testosterone's mostly protective benefits, including the brain regions, neural circuits, and cellular and molecular pathways involved. While the precise underlying mechanisms remain unclear, both activational and organizational effects of testosterone appear to contribute to these effects. Future clinical studies are necessary in order to better understand when and how testosterone therapy may be effective in both sexes.

Administration of an anabolic steroid during the adolescent phase changes the behavior, cardiac autonomic balance and fluid intake in male adult rats

Few data are available on adolescent users because most behavioral studies on anabolic-androgenic steroids (AAS) abuse have been performed in adults. Studies evaluating the impact of long-term effects of AAS abuse on the prepubertal phase are even more uncommon. Accordingly, this study was developed to test the hypothesis that changes induced by the use of AAS during the adolescent phase may be noted in the adult phase even when the AAS treatment cycle is discontinued. Therefore, not only behavioral changes but also possible autonomic and electrolyte disorders were evaluated. For this purpose, we used male prepubertal, 26-day-old (P26) Wistar rats that were treated with vehicle (control, n=10) or testosterone propionate (TP; 5 mg/kg intramuscular (IM) injection, AAS, n=10) five times per week for 5 weeks, totaling 25 applications during the treatment. Aggression tests were performed at the end of the cycle (P54-56), whereas open-field tests (OFTs), elevated plus maze (EPM) behavioral tests and measurements of heart rate variability (HRV), fluid intake and pathology were conducted in the adult phase (P87-92). The AAS group showed greater aggressiveness in the pubertal phase and higher levels of horizontal and vertical exploration and anxiety-related behavior in the adult phase than the control group (P<0.05). HRV tests showed an increase in sympathetic autonomic modulation, and hydroelectrolytic assessment showed lower basal intake levels of hypertonic saline than the control group (P<0.05), without statistically significant changes in the basal intake of water. These data together suggest that the use of AAS during the prepubertal phase induces behavioral, autonomic and hydroelectrolytic changes that manifest in the adult phase even when treatment is discontinued in late adolescence in rats.

Sex, hormones and neurogenesis in the hippocampus: hormonal modulation of neurogenesis and potential functional implications

The hippocampus is an area of the brain that undergoes dramatic plasticity in response to experience and hormone exposure. The hippocampus retains the ability to produce new neurones in most mammalian species and is a structure that is targeted in a number of neurodegenerative and neuropsychiatric diseases, many of which are influenced by both sex and sex hormone exposure. Intriguingly, gonadal and adrenal hormones affect the structure and function of the hippocampus differently in males and females. Adult neurogenesis in the hippocampus is regulated by both gonadal and adrenal hormones in a sex- and experience-dependent way. Sex differences in the effects of steroid hormones to modulate hippocampal plasticity should not be completely unexpected because the physiology of males and females is different, with the most notable difference being that females gestate and nurse the offspring. Furthermore, reproductive experience (i.e. pregnancy and mothering) results in permanent changes to the maternal brain, including the hippocampus. This review outlines the ability of gonadal and stress hormones to modulate multiple aspects of neurogenesis (cell proliferation and cell survival) in both male and female rodents. The function of adult neurogenesis in the hippocampus is linked to spatial memory and depression, and the present review provides early evidence of the functional links between the hormonal modulation of neurogenesis that may contribute to the regulation of cognition and stress.

Factors influencing behavior in the forced swim test

The forced swim test (FST) is a behavioral test in rodents which was developed in 1978 by Porsolt and colleagues as a model for predicting the clinical efficacy of antidepressant drugs. A modified version of the FST added the classification of active behaviors into swimming and climbing, in order to facilitate the differentiation between serotonergic and noradrenergic classes of antidepressant drugs. The FST is now widely used in basic research and the pharmaceutical screening of potential antidepressant treatments. It is also one of the most commonly used tests to assess depressive-like behavior in animal models. Despite the simplicity and sensitivity of the FST procedure, important differences even in baseline immobility rates have been reported between different groups, which complicate the comparison of results across studies. In spite of several methodological papers and reviews published on the FST, the need still exists for clarification of factors which can influence the procedure. While most recent reviews have focused on antidepressant effects observed with the FST, this one considers the methodological aspects of the procedure, aiming to summarize issues beyond antidepressant action in the FST. The previously published literature is analyzed for factors which are known to influence animal behavior in the FST. These include biological factors, such as strain, age, body weight, gender and individual differences between animals; influence of preconditioning before the FST: handling, social isolation or enriched environment, food manipulations, various kinds of stress, endocrine manipulations and surgery; schedule and routes of treatment, dosage and type of the drugs as well as experimental design and laboratory environmental effects. Consideration of these factors in planning experiments may result in more consistent FST results.

Depression-like behavior is dependent on age in male SAMP8 mice

Aging is associated with an increased risk of depression in humans. To elucidate the underlying mechanisms of depression and its dependence on aging, here we study signs of depression in male SAMP8 mice. For this purpose, we used the forced swimming test (FST). The total floating time in the FST was greater in SAMP8 than in SAMR1 mice at 9 months of age; however, this difference was not observed in 12-month-old mice, when both strains are considered elderly. Of the two strains, only the SAMP8 animals responded to imipramine treatment. We also applied the dexamethasone suppression test (DST) and studied changes in the dopamine and serotonin (5-HT) uptake systems, the 5-HT2a/2c receptor density in the cortex, and levels of TPH2. The DST showed a significant difference between SAMR1 and SAMP8 mice at old age. SAMP8 exhibits an increase in 5-HT transporter density, with slight changes in 5-HT2a/2c receptor density. In conclusion, SAMP8 mice presented depression-like behavior that is dependent on senescence process, because it differs from SAMR1, senescence resistant strain.

Testosterone modulates spatial recognition memory in male rats

A growing body of research indicates that testosterone influences spatial cognition in male rats; however, the overwhelming majority of studies have been conducted on tasks motivated by either food deprivation or water escape. The hippocampus-dependent version of the Y-maze task, which characterizes spatial recognition memory, capitalizes on the propensity of rats to gravitate toward novel spatial environments and is not contingent upon either appetite or the stress associated with water escape, two factors also affected by testosterone. Accordingly, the aim of the current study was to examine the effects of orchidectomy and subsequent testosterone treatment on spatial recognition memory. Orchidectomy did not impact spatial recognition memory when the delay between the information and retention trials of the Y-maze task was 24h. Alternatively, on the second Y-maze task, which featured a 48-h delay between trials, orchidectomy reduced, and treatments that produced higher levels of testosterone restored, preference for the arm associated with the novel spatial environment. Importantly, there were no differences in activity levels as a function of orchidectomy or testosterone treatment on either of the two tasks. Consistent with previous findings, orchidectomy attenuated, and testosterone treatment restored, both body weight gain and the relative weight of the androgen-sensitive ischiocavernosus muscle, which confirmed the efficacy of orchidectomy and testosterone treatments on physiological outcomes. Therefore, testosterone influenced spatial cognition on a task that minimized the influence of non-mnemonic factors and took advantage of the innate preference of rodents to seek out novel spatial environments.

Gestational or acute restraint in adulthood reduces levels of 5α-reduced testosterone metabolites in the hippocampus and produces behavioral inhibition of adult male rats

Stressors, during early life or adulthood, can alter steroid-sensitive behaviors, such as exploration, anxiety, and/or cognitive processes. We investigated if exposure to acute stressors in adulthood may alter behavioral and neuroendocrine responses of male rats that were exposed to gestational stress or not. We hypothesized that rats exposed to gestational and acute stress may show behavioral inhibition, increased corticosterone, and altered androgen levels in the hippocampus. Subjects were adult, male offspring of rat dams that were restrained daily on gestational days 14–20, or did not experience this manipulation. Immediately before testing, rats were restraint stressed for 20 min or not. During week 1, rats were tested in a battery of tasks, including the open field, elevated plus maze, social interaction, tailflick, pawlick, and defensive burying tasks. During week 2, rats were trained and tested 24 h later in the inhibitory avoidance task. Plasma corticosterone and androgen levels, and hippocampal androgen levels, were measured in all subjects. Gestational and acute restraint stress increased plasma levels of corticosterone, and reduced levels of testosterone's 5α-reduced metabolites, dihydrotestosterone (DHT) and 3α-androstanediol (3α-diol), but not the aromatized metabolite, estradiol (E₂), in plasma or the hippocampus. Gestational and acute restraint stress reduced central entries made in the open field, and latencies to enter the shock-associated side of the inhibitory avoidance chamber during testing. Gestational stress reduced time spent interacting with a conspecific. These data suggest that gestational and acute restraint stress can have actions to produce behavioral inhibition coincident with increased corticosterone and decreased 5α-reduced androgens of adult male rats. Thus, gestational stress altered neural circuits involved in the neuroendocrine response to acute stress in early adulthood.

Dissociating behavioral, autonomic, and neuroendocrine effects of androgen steroids in animal models

Developments in behavioral assessment, autonomic and/or baseline reactivity, psychopharmacology, and genetics, have contributed significantly to the assessment of performance-enhancing drugs in animal models. Particular classes of steroid hormones: androgenic steroids are of interest. Anecdotally, the performance enhancing effects of androgens are attributed to anabolic events. However, there is a discrepancy between anecdotal evidence and investigative data. While some androgen steroids may promote muscle growth (myogenesis), effects of androgens on performance enhancement are not always seen. Indeed, some effects of androgens on performance may be attributable to their psychological and cardiovascular effects. As such, we consider androgen effects in terms of their behavioral, autonomic, and neuroendocrine components. Techniques are discussed in this chapter, some of which are well established, while others have been more recently developed to study androgen action. Androgens may be considered for their positive impact, negative consequence, or psychotropic properties. Thus, this review aims to elucidate some of the effects and/or mechanisms of androgens on behavioral, autonomic, and/or neuroendocrine assessment that may underlie their controversial performance enhancing effects.

Physical activity induces depression-like behavior in intact male rats

Testosterone affects behavior. Whether regular physical training does influence these effects is unknown. The assumption that testosterone induces muscular hypertrophy if combined with physical training has not been confirmed experimentally. The aim of this study was to evaluate whether activity and/or testosterone treatment affects depression-like behavior and to observe the effects of activity and testosterone on muscle fiber diameter. Forty-three male rats were divided into 4 groups: two groups (TST act and TST lazy) were treated with testosterone (5mg/kg) and two groups were used as control (CTRL act and CTRL lazy). Two of the groups (CTRL act and TST act) underwent 2weeks of exercise. The forced swim test was used as a test of depression-like behavior. Sex steroids were measured and the diameter of skeletal muscle fibers was evaluated. Testosterone was significantly higher in both testosterone-treated groups (p<0.001). Physically active groups had higher immobility times in the forced swim test than inactive groups. Groups CTRL act and TST lazy showed significantly larger diameter of muscle fibers in comparison to the TST act group. Our results suggest that physical activity induces depression-like behavior in rats. Controversial antagonistic effects of testosterone and physical activity on muscle fiber diameter were found.

Hypogonadism predisposes males to the development of behavioural and neuroplastic depressive phenotypes

The incidence of depression is 2-3× higher in women particularly during the reproductive years, an occurrence that has been associated with levels of sex hormones. The age-related decline of testosterone levels in men corresponds with the increased acquisition of depressive symptoms, and hormone replacement therapy can be efficacious in treating depression in hypogonadal men. Although it is not possible to model depression in rodents, it is possible to model some of the symptoms of depression including a dysregulated stress response and altered neuroplasticity. Among animal models of depression, chronic mild unpredictable stress (CMS) is a common paradigm used to induce depressive-like behaviours in rodents, disrupt the hypothalamic-pituitary adrenal axis and decrease hippocampal neuroplasticity. The purpose of this study was to assess the effect of hypogonadism, produced by gonadectomy, on the acquisition of depressive-like behaviours and changes in hippocampal neuroplasticity in adult male Sprague-Dawley rats. A 21-day unpredictable CMS protocol was used on gonadectomised (GDX) and sham-operated males which produced an attenuation of weight gain in the GDX males receiving CMS treatment (GDX-CMS). Behavioural analysis was carried out to assess anxiety- and depressive-like behaviours. The combination of GDX and CMS produced greater passive behaviours within the forced swim test than CMS exposure alone. Similarly, hippocampal cell proliferation, neurogenesis and the expression of the neuroplastic protein polysialated neural cell adhesion molecule (PSA-NCAM) were all significantly reduced in the GDX-CMS group compared to all other treatment groups. These findings indicate that testicular hormones confer resiliency to chronic stress in males therefore reducing the likelihood of developing putative physiological, behavioural or neurological depressive-like phenotypes.

Stress and the pregnant female: Impact on hippocampal cell proliferation, but not affective-like behaviors

Fifteen percent of women worldwide develop postpartum depression; however, many women also suffer from mood disorders during pregnancy. Our knowledge of how these stress-related disorders affect the neurobiology of the mother is very limited. In animal models, depressive-like behavior is often associated with repeated stress and alterations in adult neurogenesis in the hippocampus. However, research has yet to investigate the effect of stress on affective-like behavior and hippocampal neurogenesis in the pregnant female. The aim of the present study was to determine whether stress during gestation alters affective-like behaviors, corticosterone levels, and hippocampal cell proliferation and new cell survival in the pregnant female, and whether these effects differ from virgin females. Age-matched pregnant and virgin Sprague-Dawley rats were divided into two conditions: 1) stress and 2) control. Females in the stress condition were repeatedly restrained during gestation, and at matched time points in virgin females. Affective-like behaviors were assessed at the end of gestation, and at matched time points in virgin females. Results demonstrate that regardless of repeated restraint stress, pregnant females have increased anxiety-like behavior, decreased depressive-like behavior, and lower corticosterone levels, compared to non-stressed, and at times stressed, virgin females. In addition, stressed virgin females have lower levels of depressive-like behavior compared to control virgin females. Interestingly, hippocampal cell proliferation was increased in both virgin and pregnant females after stress. Understanding how stress affects the female during different reproductive states will aid in improving the health and well being of the mother and child.

Effects of in utero exposure to Tityus bahiensis scorpion venom in adult rats

The toxicity of Tityus bahiensis scorpion venom is well known, but there are little data about the damage in offspring of dams that were exposed to the venom during pregnancy. The objective of this work was to determine the toxic effects of venom in adult offspring of Wistar rats exposed to venom in utero. Dams were divided into a control group, subcutaneously injected with saline solution on the 10th (GD10) and 16th (GD16) days, and two experimental groups, subcutaneously injected with venom (2.5mg/kg) on GD10 or GD16, respectively. Adult offspring were evaluated according to behavioral development and neuronal integrity in the hippocampus. Tests performed in the activity box and in the enriched environment demonstrated that males from GD10 had motor decrease. Females from GD10 showed a depressive-like state and were more anxious, as demonstrated by the forced swimming test and social interaction. The plus-maze discriminative avoidance task demonstrated that GD16 males had lower levels of anxiety. The number of neuronal cells was decreased in CA1, CA3 and CA4 hippocampal areas of males and females from GD10 group and in CA1 of females and CA4 of males from GD16 group. Thus, we conclude that venom exposure in pregnant dams causes subtle alteration in the behavioral and neuronal development of offspring in adult life in a gender-dependent manner.