Maternal exercise decreases maternal deprivation induced anxiety of pups and correlates to increased prefrontal cortex BDNF and VEGF

Early life stress shifts critical periods and causes precocious visual cortex development

The developing nervous system displays remarkable plasticity in response to sensory stimulation during critical periods of development. Critical periods may also increase the brain's vulnerability to adverse experiences. Here we show that early-life stress (ELS) in mice shifts the timing of critical periods in the visual cortex. ELS induced by animal transportation on postnatal day 12 accelerated the opening and closing of the visual cortex critical period along with earlier maturation of visual acuity. Staining of a molecular correlate that marks the end of critical period plasticity revealed premature emergence of inhibitory perineuronal nets (PNNs) following ELS. ELS also drove lasting changes in visual cortex mRNA expression affecting genes linked to psychiatric disease risk, with hemispheric asymmetries favoring the right side. NMR spectroscopy and a metabolomics approach revealed that ELS was accompanied by activated energy metabolism and protein biosynthesis. Thus, ELS may accelerate visual system development, resulting in premature opening and closing of critical period plasticity. Overall, the data suggest that ELS desynchronizes the orchestrated temporal sequence of regional brain development potentially leading to long-term functional deficiencies. These observations provide new insights into a neurodevelopmental expense to adaptative brain plasticity. These findings also suggest that shipment of laboratory animals during vulnerable developmental ages may result in long lasting phenotypes, introducing critical confounds to the experimental design.

Understanding the role of early life stress and schizophrenia on anxiety and depressive like outcomes: An experimental study

BACKGROUND

Adverse experiences due to early life stress (ELS) or parental psychopathology such as schizophrenia (SZ) have a significant implication on individual susceptibility to psychiatric disorders in the future. However, it is not fully understood how ELS affects social-associated behaviors as well as the developing prefrontal cortex (PFC).

OBJECTIVE

The aim of this study was to investigate the impact of ELS and ketamine induced schizophrenia like symptoms (KSZ) on anhedonia, social behavior and anxiety-like behavior.

METHODS

Male and female Sprague-Dawley rat pups were allocated randomly into eight experimental groups, namely control, gestational stress (GS), GS+KSZ, maternal separation (MS), MS+KSZ pups, KSZ parents, KSZ parents and Pups and KSZ pups only. ELS was induced by subjecting the pups to GS and MS, while schizophrenia like symptoms was induced through subcutaneous administration of ketamine. Behavioral assessment included sucrose preference test (SPT) and elevated plus maze (EPM), followed by dopamine testing and analysis of astrocyte density. Statistical analysis involved ANOVA and post hoc Tukey tests, revealing significant group differences and yielding insights into behavioral and neurodevelopmental impacts.

RESULTS

GS, MS, and KSZ (dams) significantly reduced hedonic response and increased anxiety-like responses (p < 0.05). Notably, the presence of normal parental mental health demonstrated a reversal of the observed decline in Glial Fibrillary Acidic Protein-positive astrocytes (GFAP+ astrocytes) (p < 0.05) and a reduction in anxiety levels, implying its potential protective influence on depressive-like symptoms and PFC astrocyte functionality.

CONCLUSION

The present study provides empirical evidence supporting the hypothesis that exposure to ELS and KSZ on dams have a significant impact on the on development of anxiety and depressive like symptoms in Sprague Dawley rats, while positive parenting has a reversal effect.

The effect of intra-nasal co-treatment with insulin and growth factor-rich serum on behavioral defects, hippocampal oxidative-nitrosative stress, and histological changes induced by icv-STZ in a rat model

Impaired insulin and growth factor functions are thought to drive many alterations in neurodegenerative diseases like dementia and seem to contribute to oxidative stress and inflammatory responses. Recent studies revealed that nasal growth factor therapy could induce neuronal and oligodendroglia protection in rodent brain damage induction models. Impairment of several growth factors signaling was reported in neurodegenerative diseases. So, in the present study, we examined the effects of intranasal co-treatment of insulin and a pool of growth factor-rich serum (GFRS) which separated from activated platelets on memory, and behavioral defects induced by intracerebroventricular streptozotocin (icv-STZ) rat model also investigated changes in the hippocampal oxidative-nitrosative state and histology. We found that icv-STZ injection (3 mg/kg bilaterally) impairs spatial learning and memory in Morris Water Maze, leads to anxiogenic-like behavior in the open field arena, and induces oxidative-nitrosative stress, neuroinflammation, and neuronal/oligodendroglia death in the hippocampus. GFRS (1µl/kg, each other day, 9 doses) and regular insulin (4 U/40 µl, daily, 18 doses) treatments improved learning, memory, and anxiogenic behaviors. The present study showed that co-treatment (GFRS + insulin with respective dose) has more robust protection against hippocampal oxidative-nitrosative stress, neuroinflammation, and neuronal/oligodendroglia survival in comparison with the single therapy. Memory and behavioral improvements in the co-treatment of insulin and GFRS could be attributed to their effects on neuronal/oligodendroglia survival and reduction of neuroinflammation in the hippocampus.

Anxiolytic effects of Enterococcus faecalis 2001 on a mouse model of colitis

Ulcerative colitis (UC) is a refractory inflammatory bowel disease, which is known to cause psychiatric disorders such as anxiety and depression at a high rate in addition to peripheral inflammatory symptoms. However, the pathogenesis of these psychiatric disorders remains mostly unknown. While prior research revealed that the Enterococcus faecalis 2001 (EF-2001) suppressed UC-like symptoms and accompanying depressive-like behaviors, observed in a UC model using dextran sulfate sodium (DSS), whether it has an anxiolytic effect remains unclear. Therefore, we examined whether EF-2001 attenuates DSS-induced anxiety-like behaviors. Treatment with 2% DSS for seven days induced UC-like symptoms and anxiety-like behavior through the hole-board test, increased serum lipopolysaccharide (LPS) and corticosterone concentration, and p-glucocorticoid receptor (GR) in the prefrontal cortex (PFC), and decreased N-methyl-D-aspartate receptor subunit (NR) 2A and NR2B expression levels in the PFC. Interestingly, these changes were reversed by EF-2001 administration. Further, EF-2001 administration enhanced CAMKII/CREB/BDNF-Drebrin pathways in the PFC of DSS-treated mice, and labeling of p-GR, p-CAMKII, and p-CREB showed colocalization with neurons. EF-2001 attenuated anxiety-like behavior by reducing serum LPS and corticosterone levels linked to the improvement of UC symptoms and by facilitating the CAMKII/CREB/BDNF-Drebrin pathways in the PFC. Our findings suggest a close relationship between UC and anxiety.

Preliminary findings of emotion regulation in 12-month-old infants of mothers enrolled in a randomized controlled trial assessing a nutrition + exercise intervention

Improved offspring emotion regulation (ER) has been associated with maternal intake of single nutrients or exercise during pregnancy but has not been examined in randomized trials. We investigated the impact of a maternal nutrition + exercise intervention during pregnancy on offspring ER at 12 months of age. Mothers in the Be Healthy In Pregnancy randomized controlled trial were randomly assigned to an individualized nutrition + exercise intervention plus usual care (UC) or UC alone (control group). A multimethod assessment of infant ER using parasympathetic nervous system function (high frequency heart rate variability [HF-HRV] and root mean square of successive differences [RMSSD]) as well as maternal reports of infant temperament (Infant Behavior Questionnaire- Revised short form) was completed with a subsample of infants of enrolled mothers (intervention = 9, control = 8). The trial was registered at www.clinicaltrials.gov (NCT01689961). We observed greater HF-HRV (M = 4.63, SD = 0.50, p = .04, ƞ² _p  = .25) and RMSSD (M = 24.25, SD = 6.15, p = .04, ƞ² _p  = .25) in infants of mothers in the intervention versus control group. Intervention group infants also had higher maternally rated surgency/extraversion (M = 5.54, SD = 0.38, p = .00, ƞ² _p  = .65) and regulation/orienting (M = 5.46, SD = 0.52, p = .02, ƞ² _p  = .81), and lower negative affectivity (M = 2.70, SD = 0.91, p = .03, ƞ² _p  = .52). These preliminary results suggest that pregnancy nutrition + exercise interventions could improve infant ER but these findings require replication in larger, more diverse samples.

The lifetime impact of stress on fear regulation and cortical function

A variety of stressful experiences can influence the ability to form and subsequently inhibit fear memory. While nonsocial stress can impact fear learning and memory throughout the lifespan, psychosocial stressors that involve negative social experiences or changes to the social environment have a disproportionately high impact during adolescence. Here, we review converging lines of evidence that suggest that development of prefrontal cortical circuitry necessary for both social experiences and fear learning is altered by stress exposure in a way that impacts both social and fear behaviors throughout the lifespan. Further, we suggest that psychosocial stress, through its impact on the prefrontal cortex, may be especially detrimental during early developmental periods characterized by higher sociability. This article is part of the Special Issue on 'Fear, Anxiety and PTSD'.

Direct and Inherited Epigenetic Changes in the Nervous System Caused by Intensive Locomotion: Possible Adaptive Significance

Abstract

This review is devoted to the analysis of works that investigated the long-term effects of species-specific forms of intensive locomotion on the cognitive functions of animals and humans, which can be transmitted to the next generation. To date, the anxiolytic and cognitive-enhancing long-term effects of intensive locomotion have been demonstrated in humans, rodents, fish, insects, mollusks, and nematodes. In rodents, changes in the central nervous system caused by intense locomotion can be transmitted through the maternal and paternal line to the descendants of the first generation. These include reduced anxiety, improved spatial learning and memory, increased levels of brain neurotrophic factor and vascular endothelial growth factor in the hippocampus and frontal cortex. The shift of the balance of histone acetylation in the hippocampus of rodents towards hyperacetylation, and the balance of DNA methylation towards demethylation manifests itself both as a direct and as a first-generation inherited effect of motor activity. The question about the mechanisms that link locomotion with an increase in the plasticity of a genome in the brain of descendants remains poorly understood, and invertebrate model organisms can be an ideal object for its study. Currently, there is a lack of a theoretical model explaining why motor activity leads to long-term improvement of some cognitive functions that can be transmitted to the next generation and why such an influence could have appeared in evolution. The answer to these questions is not only of fundamental interest, but it is necessary for predicting therapeutic and possible side effects of motor activity in humans. In this regard, the article pays special attention to the review of ideas on the evolutionary aspects of the problem. We propose our own hypothesis, according to which the activating effect of intensive locomotion on the function of the nervous system could have been formed in evolution as a preadaptation to a possible entry into a new environment.

Beneficial intergenerational effects of exercise on brain and cognition: a multilevel meta-analysis of mean and variance

Physical exercise not only helps to improve physical health but can also enhance brain development and cognition. Recent reports on parental (both maternal and paternal) effects raise the possibility that parental exercise may provide benefits to offspring through intergenerational inheritance. However, the general magnitude and consistency of parental exercise effects on offspring is still controversial. Additionally, empirical research has long overlooked an important aspect of exercise: its effects on variability in neurodevelopmental and cognitive traits. Here, we compiled data from 52 studies involving 4786 rodents (412 effect sizes) to quantify the intergenerational transmission of exercise effects on brain and cognition. Using a multilevel meta-analytic approach, we found that, overall, parental exercise showed a tendency for increasing their offspring's brain structure by 12.7% (albeit statistically non-significant) probably via significantly facilitating neurogenesis (16.5%). Such changes in neural anatomy go in hand with a significant 20.8% improvement in neurobehaviour (improved learning and memory, and reduced anxiety). Moreover, we found parental exercise significantly reduces inter-individual differences (i.e. reduced variance in the treatment group) in progeny's neurobehaviour by 10.2% (coefficient of variation ratio, lnCVR), suggesting the existence of an individual by intervention interaction. The positive effects of exercise are modulated by several covariates (i.e. moderators), such as the exercised parent's sex, offspring's sex, and age, mode of exercise, and exercise timing. In particular, parental forced exercise is more efficient than voluntary exercise at significantly improving offspring neurobehaviour (26.0%) and reducing its variability (14.2%). We observed larger effects when parental exercise started before pregnancy. However, exercising only during pregnancy also had positive effects. Mechanistically, exercise significantly upregulated brain-derived neurotrophic factor (BDNF) by 28.9%, vascular endothelial growth factor (VEGF) by 35.8%, and significantly decreased hippocampal DNA methylation by 3.5%, suggesting that brain growth factor cascades and epigenetic modifications can moderate the transmission of parental exercise effects. Collectively, by coupling mean with variance effects, our analyses draw a more integrated picture of the benefits that parental exercise has on offspring: not only does it improve offspring brain development and cognitive performance, but it also reduces inter-individual differences in cognition-related traits. We advocate that meta-analysis of variation together with the mean of a trait provides novel insights for old controversies as well as emerging new questions, opening up a new era for generating variance-based hypotheses.

Effects of running before pregnancy on long-term memory and hippocampal alterations induced by prenatal stress

Studies have shown that an adverse environment in utero influences fetal growth and development, leading to several neuroendocrine and behavioral changes in adult life. Nevertheless, the mechanisms involved in the long-term benefits of pregestational exercise are still poorly understood. Thus, this study aimed to evaluate the effects of physical exercise before the gestational period on memory behavior and gene expression in the hippocampus of adult mice submitted to prenatal stress. Female Balb/c mice were divided into three groups: control (CON), prenatal restraint stress (PNS), and exercise before the gestational period plus PNS (EX + PNS). When adults, male and female offspring were submitted to the object recognition test followed by the hippocampal evaluation of BDNF exons I and IV mRNA expression, as well as hypothalamic-pituitary-adrenal axis related genes. Pregestational exercise did not prevent the decreased recognition index, as well as GR and CRHR1 gene expression observed in PNS males. Conversely, prenatal stress did not influence female memory behavior. Moreover, exercise attenuated the effects of prenatal stress on female BDNF IV gene expression. The results indicate that pregestational exercise was able to prevent the effects of maternal stress on hippocampal BDNF IV gene expression in females, although no effects were seen on the stress-induced memory impairment in males.

Regular aerobic exercise increased VEGF levels in both soleus and gastrocnemius muscles correlated with hippocampal learning and VEGF levels

Physical exercise improves learning and memory abilities by increasing the levels of several growth factors in the hippocampus. One growth factor, vascular endothelial growth factor (VEGF), is primarily produced in the muscles and not only increases in the periphery during exercise but can also cross the blood-brain barrier. The aim of this study is to investigate the effects of regular aerobic chronic exercise on different types of muscle fibers and the relationships between learning/memory and muscle induced-VEGF. Following a one-week adaptation period, male rats underwent treadmill training at a speed of 8 m/min for 30 min daily, 3 days a week for 6 weeks. Memory functions were evaluated using the Morris water maze. VEGF, superoxide dismutase (SOD), glutathione peroxidase (GPx), and malondialdehyde (MDA) levels were measured in type 1 and type 2 muscle fibers and VEGF levels were also measured in the hippocampus. Exercise positively affected both learning and memory and also increased VEGF levels in both muscle fiber types. Muscle VEGF levels positively correlate with hippocampal learning and hippocampal VEGF levels. Exercise reduced both SOD and MDA levels in type 1 and type 2 muscle fibers, whereas GPx levels decreased only in type 2 muscle fibers. Our findings suggest that regular aerobic exercise elevates VEGF levels and diminishes oxidative stress in both fiber types. Exercise-induced VEGF levels in both type 1 and 2 muscle fibers appear to be associated with the positive effect of exercise on learning and memory function and is accompanied by an increase in VEGF levels in the hippocampus. Further research is needed to elucidate the exact mechanism by which fiber type-specific VEGF mediates hippocampal neurogenesis and angiogenesis.

Physical exercise improves learning and memory abilities by increasing the levels of several growth factors in the hippocampus. One growth factor, vascular endothelial growth factor (VEGF), is primarily produced in the muscles and not only increases in the periphery during exercise but can also cross the blood-brain barrier. The aim of this study is to investigate the effects of regular aerobic chronic exercise on different types of muscle fibers and the relationships between learning/memory and muscle induced-VEGF. Following a one-week adaptation period, male rats underwent treadmill training at a speed of 8 m/min for 30 min daily, 3 days a week for 6 weeks. Memory functions were evaluated using the Morris water maze. VEGF, superoxide dismutase (SOD), glutathione peroxidase (GPx), and malondialdehyde (MDA) levels were measured in type 1 and type 2 muscle fibers and VEGF levels were also measured in the hippocampus. Exercise positively affected both learning and memory and also increased VEGF levels in both muscle fiber types. Muscle VEGF levels positively correlate with hippocampal learning and hippocampal VEGF levels. Exercise reduced both SOD and MDA levels in type 1 and type 2 muscle fibers, whereas GPx levels decreased only in type 2 muscle fibers. Our findings suggest that regular aerobic exercise elevates VEGF levels and diminishes oxidative stress in both fiber types. Exercise-induced VEGF levels in both type 1 and 2 muscle fibers appear to be associated with the positive effect of exercise on learning and memory function and is accompanied by an increase in VEGF levels in the hippocampus. Further research is needed to elucidate the exact mechanism by which fiber type-specific VEGF mediates hippocampal neurogenesis and angiogenesis.

Investigating the link between serum concentrations of brain-derived neurotrophic factor and behavioral measures in anxious alcohol-dependent individuals

Brain-derived neurotrophic factor (BDNF) plays a role in different neurophysiological processes, including those involved in alcohol- and anxiety-related behaviors. Preclinical and clinical studies indicate that chronic excessive alcohol use leads to a downregulation of BDNF production in the periphery and in the brain. In addition, a decrease in BDNF concentrations in the blood has been reported to be associated with increased anxiety levels. Non-treatment-seeking alcohol-dependent individuals with high trait anxiety were studied to assess whether serum BDNF concentrations may be linked to self-reported levels of alcohol drinking, anxiety, and other behavioral measures. Participants had a current diagnosis of alcohol dependence, high trait anxiety score, and were not seeking treatment for alcohol dependence or anxiety. A fasting blood sample was collected from each participant and serum BDNF was measured using an enzyme-linked immunosorbent assay (ELISA). Behavioral data were collected on the same day, including measures of alcohol drinking, craving, dependence severity, and anxiety. Bivariate correlations were run between BDNF levels and behavioral measures. Serum BDNF concentrations were negatively correlated with average drinks per drinking days (r = -0.41, p = 0.02) and positively correlated with obsessive-compulsive drinking scale (r = 0.48, p = 0.007) and state-trait anxiety inventory (r = 0.52, p = 0.003) scores. These findings shed light on the possible role of the BDNF system in the neurobiology of alcohol- and anxiety-related behaviors.

Empathy as a Concept from Bench to Bedside: A Translational Challenge

Empathy is a multidimensional paradigm, and there currently is a lack of scientific consensus in its definition. In this paper, we review the possibility of compromising data during behavioral neuroscience experiments, including but not limited to those who study empathy. The experimental protocols can affect, and be affected by, empathy and related processes at multiple levels. We discuss several points to help researchers develop a successful translational pathway for behavioral research on empathy. Despite varying in their focus with no widely accepted model, current rodent models on empathy have provided sound translational explanations for many neuropsychiatric proof-of-concepts to date. Research has shown that empathy can be influenced by many parameters, some of which are to be reviewed in this paper. We emphasize the future importance of consistency in modeling proof of concept; efforts to create a multidisciplinary group which would include both bench scientists and clinicians with expertise in neuropsychiatry, and the consideration of empathy as an independent variable in animal behavioral experimental designs which is not the mainstream practice at present.

Interleukin-18 levels in the hippocampus and behavior of adult rat offspring exposed to prenatal restraint stress during early and late pregnancy

Exposure to maternal stress during prenatal life is associated with an increased risk of neuropsychiatric disorders, such as depression and anxiety, in offspring. It has also been increasingly observed that prenatal stress alters the phenotype of offspring via immunological mechanisms and that immunological dysfunction, such as elevated interleukin-18 levels, has been reported in cultures of microglia. Prenatal restraint stress (PRS) in rats permits direct experimental investigation of the link between prenatal stress and adverse outcomes. However, the majority of studies have focused on the consequences of PRS delivered in the second half of pregnancy, while the effects of early prenatal stress have rarely been examined. Therefore, pregnant rats were subjected to PRS during early/middle and late gestation (days 8-14 and 15-21, respectively). PRS comprised restraint in a round plastic transparent cylinder under bright light (6500 lx) three times per day for 45 minutes. Differences in interleukin-18 expression in the hippocampus and in behavior were compared between offspring rats and control rats on postnatal day 75. We found that adult male offspring exposed to PRS during their late prenatal periods had higher levels of anxiety-related behavior and depression than control rats, and both male and female offspring exhibited higher levels of depression-related behavior, impaired recognition memory and diminished exploration of novel objects. Moreover, an elevated level of interleukin-18 was observed in the dorsal and ventral hippocampus of male and female early- and late-PRS offspring rats. The results indicate that PRS can cause anxiety and depression-related behaviors in adult offspring and affect the expression of interleukin-18 in the hippocampus. Thus, behavior and the molecular biology of the brain are affected by the timing of PRS exposure and the sex of the offspring. All experiments were approved by the Animal Experimentation Ethics Committee at Kunming Medical University, China (approval No. KMMU2019074) in January 2019.

Early weaning increases anxiety via brain-derived neurotrophic factor signaling in the mouse prefrontal cortex

Deprivation of maternal care during early development markedly affects emotional development, but the underlying neuromolecular mechanisms are not fully understood. In a mouse model of disrupted mother-infant relationship, early weaning causes long-term impacts on pups to exhibit increased corticosterone secretion, anxiety, and stress responses in their adulthood. Revealing the molecular mechanisms behind it would beneficial to ameliorating mental problems caused by abuse in childhood. We report that normalizing circulating corticosterone in early-weaned mice, either in adulthood or soon after weaning, ameliorated anxiety levels assessed in the plus maze test. Administering a glucocorticoid receptor antagonist into the prefrontal cortex (PFC) reversed the effects of early weaning, whereas administering corticosterone increased anxiety levels, suggesting that the PFC is corticosterone’s target brain region. In the PFCs of early-weaned mice, we observed prolonged reductions in the expression of brain-derived neurotrophic factor (BDNF) and associated mRNAs. Anxiety in early-weaned mice was ameliorated by pretreatment with BDNF or a BDNF receptor agonist. In summary, early weaning increased anxiety levels by modulating glucocorticoid and BDNF signaling in the PFC.

Exercise as a Positive Modulator of Brain Function

Various forms of exercise have been shown to prevent, restore, or ameliorate a variety of brain disorders including dementias, Parkinson's disease, chronic stress, thyroid disorders, and sleep deprivation, some of which are discussed here. In this review, the effects on brain function of various forms of exercise and exercise mimetics in humans and animal experiments are compared and discussed. Possible mechanisms of the beneficial effects of exercise including the role of neurotrophic factors and others are also discussed.

Preventive Effect of Maternal Forced Exercise on Offspring Pain Perception and Intensity: The Role of 5-HT2 and D2 Receptors

BACKGROUND

Many previous studies showed that maternal forced exercise can reduce some central disorders in offsprings, but its clear mechanism remains unclear. In this study, the role of 5-HT2 and D2 receptors in neuroprotective effects of maternal forced exercise in offspring neurodevelopment and effect on some behaviors were evaluated.

MATERIALS AND METHODS

Forty-eight pregnant rats were trained by forced exercise, and some behavioral assays in their offspring were performed in the presence and absence of 5-HT2 and D2 receptor antagonists in various experimental groups.

RESULTS

Our data showed that maternal forced exercise caused increase in latency of pain perception in offsprings in hot plate test, writhing test (WT), and tail flick test. Furthermore, a decrease in intensity was shown by WT. On the other hand, treatment of mothers by forced exercise in combination with 5-HT2 and D2 receptor antagonists could inhibit these effects of forced exercise and cause disturbances in pain perception and intensity.

CONCLUSION

Our data suggested that maternal forced exercise causes protective effects on offspring pain perception and intensity, and in this effect, 5-HT2 and D2 receptors are probably involved.

The effect of maternal forced exercise on offspring pain perception, motor activity and anxiety disorder: the role of 5-HT2 and D2 receptors and CREB gene expression

The effect of maternal forced exercise on central disorders in offsprings has been shown but the mechanism is still unclear. In this study, the role of 5-HT2 and D2 receptors in neuroprotective effects of maternal forced exercise on offspring neurodevelopment and neurobehavioral symptoms is evaluated. Sixty pregnant rats were trained by forced exercise and some behavioral and molecular aspects in their offspring were evaluated in presence of 5-HT2 and D2 receptors agonists and antagonists. The results showed that maternal forced exercise causes increase of pain tolerability and increase latency of pain perception in offspring in hot plate test, writhing test and tail flick test. Also maternal forced exercise causes decrease of depression and anxiety like behavior in offsprings. On the other hand, treatment of mothers by forced exercise in combination with 5-HT2 and D2 receptor antagonists inhibited the protective effects of forced exercise and cause disturbance in pain perception and tolerability and increase depression and anxiety in offsprings. Also expression of cyclic AMP response element binding protein (CREB) was changed in all experimental groups. In conclusion, our data suggested that maternal forced exercise causes neurobehavioral protective effect on offsprings and this effect might probably be mediated by 5-HT2 and D2 receptors and activation of CREB gene expression.

Neonatal alcohol exposure reduces number of parvalbumin-positive interneurons in the medial prefrontal cortex and impairs passive avoidance acquisition in mice deficits not rescued from exercise

Developmental alcohol exposure causes a host of cognitive and neuroanatomical abnormalities, one of which is impaired executive functioning resulting from medial prefrontal cortex (mPFC) damage. This study determined whether third-trimester equivalent alcohol exposure reduced the number of mPFC GABAergic parvalbumin-positive (PV+) interneurons, hypothesized to play an important role in local inhibition of the mPFC. The impact on passive avoidance learning and the therapeutic role of aerobic exercise in adulthood was also explored. Male C57BL/6J mice received either saline or 5g/kg ethanol (two doses, two hours apart) on PD 5, 7, and 9. On PD 35, animals received a running wheel or remained sedentary for 48days before behavioral testing and perfusion on PD 83. The number of PV+ interneurons was stereologically measured in three separate mPFC subregions: infralimbic, prelimbic and anterior cingulate cortices (ACC). Neonatal alcohol exposure decreased number of PV+ interneurons and volume of the ACC, but the other regions of the mPFC were spared. Alcohol impaired acquisition, but not retrieval of passive avoidance, and had no effect on motor performance on the rotarod. Exercise had no impact on PV+ cell number, mPFC volume, or acquisition of passive avoidance, but enhanced retrieval in both control and alcohol-exposed groups, and enhanced rotarod performance in the control mice. Results support the hypothesis that part of the behavioral deficits associated with developmental alcohol exposure are due to reduced PV+ interneurons in the ACC, but unfortunately exercise does not appear to be able to reverse any of these deficits.

Ancestral Exposure to Stress Generates New Behavioral Traits and a Functional Hemispheric Dominance Shift

In a continuously stressful environment, the effects of recurrent prenatal stress (PS) accumulate across generations and generate new behavioral traits in the absence of genetic variation. Here, we investigated if PS or multigenerational PS across 4 generations differentially affect behavioral traits, laterality, and hemispheric dominance in male and female rats. Using skilled reaching and skilled walking tasks, 3 findings support the formation of new behavioral traits and shifted laterality by multigenerational stress. First, while PS in the F1 generation did not alter paw preference, multigenerational stress in the F4 generation shifted paw preference to favor left-handedness only in males. Second, multigenerational stress impaired skilled reaching and skilled walking movement abilities in males, while improving these abilities in females beyond the levels of controls. Third, the shift toward left-handedness in multigenerationally stressed males was accompanied by increased dendritic complexity and greater spine density in the right parietal cortex. Thus, cumulative multigenerational stress generates sexually dimorphic left-handedness and dominance shift toward the right hemisphere in males. These findings explain the origins of apparently heritable behavioral traits and handedness in the absence of DNA sequence variations while proposing epigenetic mechanisms.

Chronic Light Exposure in the Middle of the Night Disturbs the Circadian System and Emotional Regulation

In mammals, the circadian system is composed of a principal circadian oscillator located in the suprachiasmatic nucleus (SCN) and a number of subordinate oscillators in extra-SCN brain regions and peripheral tissues/organs. However, how the time-keeping functions of this multiple oscillator circuit are affected by aberrant lighting environments remains largely unknown. In the present study, we investigated the effects of chronic light exposure in the middle of the night on the circadian system by comparing the mice housed in a 12:4:4:4-h L:DLD condition with the controls in 12:12-h L:D condition. Daily rhythms in locomotor activity were analyzed and the expression patterns of protein products of clock genes Period1 and Period2 (PER1 and PER2) were examined in the SCN and extra-SCN brain regions, including the dorsal striatum, hippocampus, paraventricular nucleus (PVN), and basolateral amygdala (BLA). Following 2 weeks of housing in the L:DLD condition, animals showed disturbed daily rhythms in locomotor activity and lacked daily rhythms of PER1 and PER2 in the SCN. In the extra-SCN brain regions, the PER1 and PER2 rhythms were affected in a region-specific pattern, such that they were relatively undisturbed in the striatum and hippocampus, phase-shifted in the BLA, and abolished in the PVN. In addition, mice in the L:DLD condition showed increased anxiety-like behaviors and reduced brain-derived neurotropic factor messenger RNA expression in the hippocampus, amygdala, and medial prefrontal cortex, which are brain regions that are involved in emotional regulation. These results indicate that nighttime light exposure leads to circadian disturbances not only by abolishing the circadian rhythms in the SCN but also by inducing misalignment among brain oscillators and negatively affects emotional processing. These observations serve to identify risks associated with decisions regarding lifestyle in our modern society.

Behavioral benefits of maternal swimming are counteracted by neonatal hypoxia-ischemia in the offspring

Hypoxia-ischemia (HI) represents one of the most common causes of neonatal encephalopathy. The central nervous system injury comprises several mechanisms, including inflammatory, excitotoxicity, and redox homeostasis unbalance leading to cell death and cognitive impairment. Exercise during pregnancy is a potential therapeutic tool due to benefits offered to mother and fetus. Swimming during pregnancy elicits a strong metabolic programming in the offspring's brain, evidenced by increased antioxidant enzymes, mitochondrial biogenesis, and neurogenesis. This article aims to evaluate whether the benefits of maternal exercise are able to prevent behavioral brain injury caused by neonatal HI. Female adult Wistar rats swam before and during pregnancy (30min/day, 5 days/week, 4 weeks). At 7(th) day after birth, the offspring was submitted to HI protocol and, in adulthood (60(th) day), it performed the behavioral tests. It was observed an increase in motor activity in the open field test in HI-rats, which was not prevented by maternal exercise. The rats subjected to maternal swimming presented an improved long-term memory in the object recognition task, which was totally reversed by neonatal HI encephalopathy. BDNF brain levels were not altered; suggesting that HI or maternal exercise effects were BDNF-independent. In summary, our data suggest a beneficial long-term effect of maternal swimming, despite not being robust enough to protect from HI injury.

Maternal Exercise during Pregnancy Increases BDNF Levels and Cell Numbers in the Hippocampal Formation but Not in the Cerebral Cortex of Adult Rat Offspring

Clinical evidence has shown that physical exercise during pregnancy may alter brain development and improve cognitive function of offspring. However, the mechanisms through which maternal exercise might promote such effects are not well understood. The present study examined levels of brain-derived neurotrophic factor (BDNF) and absolute cell numbers in the hippocampal formation and cerebral cortex of rat pups born from mothers exercised during pregnancy. Additionally, we evaluated the cognitive abilities of adult offspring in different behavioral paradigms (exploratory activity and habituation in open field tests, spatial memory in a water maze test, and aversive memory in a step-down inhibitory avoidance task). Results showed that maternal exercise during pregnancy increased BDNF levels and absolute numbers of neuronal and non-neuronal cells in the hippocampal formation of offspring. No differences in BDNF levels or cell numbers were detected in the cerebral cortex. It was also observed that offspring from exercised mothers exhibited better cognitive performance in nonassociative (habituation) and associative (spatial learning) mnemonic tasks than did offspring from sedentary mothers. Our findings indicate that maternal exercise during pregnancy enhances offspring cognitive function (habituation behavior and spatial learning) and increases BDNF levels and cell numbers in the hippocampal formation of offspring.

Voluntary exercise partially reverses neonatal alcohol-induced deficits in mPFC layer II/III dendritic morphology of male adolescent rats

Developmental alcohol exposure in humans can produce a wide range of deficits collectively referred to as fetal alcohol spectrum disorders (FASD). FASD-related impairments in executive functioning later in life suggest long-term damage to the prefrontal cortex (PFC). In rodent neonates, moderate to high levels of alcohol exposure decreased frontal lobe brain size and altered medial PFC pyramidal neuron dendritic morphology. Previous research in our lab demonstrated that neonatal alcohol exposure decreased basilar dendritic complexity but did not affect spine density in Layer II/III pyramidal neurons in 26- to 30-day-old rats. The current study adds to the literature by evaluating the effect of neonatal alcohol exposure on mPFC Layer II/III basilar dendritic morphology in adolescent male rats. Additionally, it examines the potential for voluntary exercise to mitigate alcohol-induced deficits on mPFC dendritic complexity. An animal model of binge drinking during the third trimester of pregnancy was used. Rats were intubated with alcohol (alcohol-exposed, AE; 5.25 g kg(-1) day(-1)) on postnatal days (PD) 4-9; two control groups were included (suckle control and sham-intubated). Rats were anesthetized and perfused with heparinized saline solution on PD 42, and brains were processed for Golgi-Cox staining. Developmental alcohol exposure decreased spine density and dendritic complexity of basilar dendrites of Layer II/III neurons in the medial PFC (mPFC) compared to dendrites of control animals. Voluntary exercise increased spine density and dendritic length in AE animals resulting in elimination of the differences between AE and SH rats. Thus, voluntary exercise during early adolescence selectively rescued alcohol-induced morphological deficits in the mPFC.

Effects of voluntary and involuntary exercise on cognitive functions, and VEGF and BDNF levels in adolescent rats

Regular treadmill running during adolescence improves learning and memory in rats. During adolescence, the baseline level of stress is thought to be greater than during other periods of life. We investigated the effects of voluntary and involuntary exercise on the prefrontal cortex and hippocampus, vascular endothelial growth factor (VEGF), brain-derived neurotrophic factor (BDNF) levels, and spatial learning, memory and anxiety in adolescent male and female rats. The voluntary exercise group was given free access to a running wheel for 6 weeks. The involuntary exercise group was forced to run on a treadmill for 30 min at 8 m/min 5 days/week for 6 weeks. Improved learning was demonstrated in both exercise groups compared to controls. Neuron density in the CA1 region of the hippocampus, dentate gyrus and prefrontal cortex were increased. Hippocampal VEGF and BDNF levels were increased in both exercise groups compared to controls. In females, anxiety and corticosterone levels were decreased; BDNF and VEGF levels were higher in the voluntary exercise group than in the involuntary exercise group. The adolescent hippocampus is affected favorably by regular exercise. Although no difference was found in anxiety levels as a result of involuntary exercise in males, females showed increased anxiety levels, and decreased VEGF and BDNF levels in the prefrontal cortex after involuntary exercise.

Potential novel biomarkers for diabetic testicular damage in streptozotocin-induced diabetic rats: nerve growth factor Beta and vascular endothelial growth factor

Background. It is well known that diabetes mellitus may cause testicular damage. Vascular endothelial growth factor (VEGF) and nerve growth factor beta (NGF-β) are important neurotrophic factors for male reproductive system. Objective. We aimed to investigate the correlation between testicular damage and testicular VEGF and NGF-β levels in diabetic rats. Methods. Diabetes was induced by streptozotocin (STZ, 45 mg/kg/i.p.) in adult rats. Five weeks later testicular tissue was removed; testicular VEGF and NGF-β levels were measured by ELISA. Testicular damage was detected by using hematoxylin and eosin staining and periodic acid-Schiff staining, and apoptosis was identified by terminal-deoxynucleotidyl-transferase-mediated dUTP nick end labeling (TUNEL). Seminiferous tubular sperm formation was evaluated using Johnsen's score. Results. In diabetic rats, seminiferous tubule diameter was found to be decreased; basement membrane was found to be thickened in seminiferous tubules and degenerated germ cells. Additionally, TUNEL-positive cells were increased in number of VEGF+ cells and levels of VEGF and NGF-β were decreased in diabetic testes. Correlation between VEGF and NGF-β levels was strong. Conclusion. These results suggest that the decrease of VEGF and NGF-β levels is associated with the increase of the apoptosis and testicular damage in diabetic rats. Testis VEGF and NGF-β levels could be potential novel biomarkers for diabetes induced testicular damage.

How cigarette smoking may increase the risk of anxiety symptoms and anxiety disorders: a critical review of biological pathways

Multiple studies have demonstrated an association between cigarette smoking and increased anxiety symptoms or disorders, with early life exposures potentially predisposing to enhanced anxiety responses in later life. Explanatory models support a potential role for neurotransmitter systems, inflammation, oxidative and nitrosative stress, mitochondrial dysfunction, neurotrophins and neurogenesis, and epigenetic effects, in anxiety pathogenesis. All of these pathways are affected by exposure to cigarette smoke components, including nicotine and free radicals. This review critically examines and summarizes the literature exploring the role of these systems in increased anxiety and how exposure to cigarette smoke may contribute to this pathology at a biological level. Further, this review explores the effects of cigarette smoke on normal neurodevelopment and anxiety control, suggesting how exposure in early life (prenatal, infancy, and adolescence) may predispose to higher anxiety in later life. A large heterogenous literature was reviewed that detailed the association between cigarette smoking and anxiety symptoms and disorders with structural brain changes, inflammation, and cell-mediated immune markers, markers of oxidative and nitrosative stress, mitochondrial function, neurotransmitter systems, neurotrophins and neurogenesis. Some preliminary data were found for potential epigenetic effects. The literature provides some support for a potential interaction between cigarette smoking, anxiety symptoms and disorders, and the above pathways; however, limitations exist particularly in delineating causative effects. The literature also provides insight into potential effects of cigarette smoke, in particular nicotine, on neurodevelopment. The potential treatment implications of these findings are discussed in regards to future therapeutic targets for anxiety. The aforementioned pathways may help mediate increased anxiety seen in people who smoke. Further research into the specific actions of nicotine and other cigarette components on these pathways, and how these pathways interact, may provide insights that lead to new treatment for anxiety and a greater understanding of anxiety pathogenesis.

Evidences that maternal swimming exercise improves antioxidant defenses and induces mitochondrial biogenesis in the brain of young Wistar rats

Physical exercise during pregnancy has been considered beneficial to mother and child. Recent studies showed that maternal swimming improves memory in the offspring, increases hippocampal neurogenesis and levels of neurotrophic factors. The objective of this work was to investigate the effect of maternal swimming during pregnancy on redox status and mitochondrial parameters in brain structures from the offspring. Adult female Wistar rats were submitted to five swimming sessions (30 min/day) prior to mating with adult male Wistar rats, and then trained during the pregnancy (five sessions of 30-min swimming/week). The litter was sacrificed when 7 days old, when cerebellum, parietal cortex, hippocampus, and striatum were dissected. We evaluated the production of reactive species and antioxidant status, measuring the activities of superoxide-dismutase (SOD), catalase (CAT) and glutathione-peroxidase (GPx), as well as non-enzymatic antioxidants. We also investigated a potential mitochondrial biogenesis regarding mitochondrion mass and membrane potential, through cytometric approaches. Our results showed that maternal swimming exercise promoted an increase in reactive species levels in cerebellum, parietal cortex, and hippocampus, demonstrated by an increase in dichlorofluorescein oxidation. Mitochondrial superoxide was reduced in cerebellum and parietal cortex, while nitrite levels were increased in cerebellum, parietal cortex, hippocampus, and striatum. Antioxidant status was improved in cerebellum, parietal cortex, and hippocampus. SOD activity was increased in parietal cortex, and was not altered in the remaining brain structures. CAT and GPx activities, as well as non-enzymatic antioxidant potential, were increased in cerebellum, parietal cortex, and hippocampus of rats whose mothers were exercised. Finally, we observed an increased mitochondrial mass and membrane potential, suggesting mitochondriogenesis, in cerebellum and parietal cortex of pups subjected to maternal swimming. In conclusion, maternal swimming exercise induced neurometabolic programing in the offspring that could be of benefit to the rats against future cerebral insults.

Maternal exercise during pregnancy ameliorates the postnatal neuronal impairments induced by prenatal restraint stress in mice

Clinical and preclinical studies have demonstrated that prenatal stress (PS) induces neuronal and behavioral disturbances in the offspring. In the present study, we determined whether maternal voluntary wheel running (VWR) during pregnancy could reverse the putative deleterious effects of PS on the neurodevelopment and behavior of the offspring. Pregnant CF-1 mice were randomly assigned to control, restraint stressed or restraint stressed+VWR groups. Dams of the stressed group were subjected to restraint stress between gestational days 14 and delivery, while control pregnant dams remained undisturbed in their home cages. Dams of the restraint stressed+VWR group were subjected to exercise between gestational days 1 and 17. On postnatal day 23 (P23), male pups were assigned to one of the following experimental groups: mice born from control dams, stressed dams or stressed+VWR dams. Locomotor behavior and pyramidal neuronal morphology were evaluated at P23. Animals were then sacrificed, and Golgi-impregnated pyramidal neurons of the parietal cortex were morphometrically analyzed. Here, we present two major findings: first, PS produced significantly diminished dendritic growth of parietal neurons without altered locomotor behavior of the offspring; and second, maternal VWR significantly offset morphological impairments.

Chotosan ameliorates cognitive and emotional deficits in an animal model of type 2 diabetes: possible involvement of cholinergic and VEGF/PDGF mechanisms in the brain

BACKGROUND

Diabetes is one of the risk factors for cognitive deficits such as Alzheimer's disease. To obtain a better understanding of the anti-dementia effect of chotosan (CTS), a Kampo formula, we investigated its effects on cognitive and emotional deficits of type 2 diabetic db/db mice and putative mechanism(s) underlying the effects.

METHODS

Seven-week-old db/db mice received daily administration of CTS (375 - 750 mg/kg, p.o.) and the reference drug tacrine (THA: 2.5 mg/kg, i.p.) during an experimental period of 7 weeks. From the age of 9-week-old, the animals underwent the novel object recognition test, the modified Y-maze test, and the water maze test to elucidate cognitive performance and the elevated plus maze test to elucidate anxiety-related behavior. After completing behavioral studies, Western blotting and immunohistochemical studies were conducted.

RESULTS

Compared with age-matched non-diabetic control strain (m/m) mice, db/db mice exhibited impaired cognitive performance and an increased level of anxiety. CTS ameliorated cognitive and emotional deficits of db/db mice, whereas THA improved only cognitive performance. The phosphorylated levels of Akt and PKCα in the hippocampus were significantly lower and higher, respectively, in db/db mice than in m/m mice. Expression levels of the hippocampal cholinergic marker proteins and the number of the septal cholinergic neurons were also reduced in db/db mice compared with those in m/m mice. Moreover, the db/db mice had significantly reduced levels of vasculogenesis/angiogenesis factors, vascular endothelial growth factor (VEGF), VEGF receptor type 2, platelet-derived growth factor-B, and PDGF receptor β, in the hippocampus. CTS and THA treatment reversed these neurochemical and histological alterations caused by diabetes.

CONCLUSION

These results suggest that CTS ameliorates diabetes-induced cognitive deficits by protecting central cholinergic and VEGF/PDGF systems via Akt signaling pathway and that CTS exhibits the anxiolytic effect via neuronal mechanism(s) independent of cholinergic or VEGF/PDGF systems in db/db mice.

Maternal treadmill exercise during pregnancy decreases anxiety and increases prefrontal cortex VEGF and BDNF levels of rat pups in early and late periods of life

In a previous study we demonstrated that, regular aerobic exercise during pregnancy decreased maternal deprivation induced anxiety. The purpose of this study is to investigate whether the positive effects of maternal exercise on the male and female offspring's early and late period of life. Half of the test subjects in each group were evaluated when they were 26 days old, and the other half were evaluated when they were 4 months old. The anxiety levels of maternally exercised groups were less than the control groups in both sexes and in both prepubertal and adult periods. The locomotor activity more increased in females. The prefrontal VEGF and BDNF levels were greater for both age groups and sexes in the maternally exercised group compared to control group. Moreover, there was a strong positive correlations between prefrontal cortex BDNF levels and results of open field tests; and VEGF levels and results of elevated plus maze tests. There was no difference in serum corticosterone levels between groups. These results indicate that maternal exercise during pregnancy may protect the pups from anxiety in early and late periods of life, and affects the prefrontal cortex positively.