Reduction In Anxiety-like Behavior Research Articles

BV2-derived extracellular vesicles modulate microglia inflammatory profile, neuronal plasticity, and behavioural performances in late adult mice

BackgroundDuring aging, both the brain and the immune system undergo a progressive impairment of physiological functions. Microglia, the immunocompetent cells of the central nervous system, shift towards a chronic mild inflammatory state that impacts brain homeostasis. Extracellular vesicles (EVs) released by microglia transport packages of molecular information that mirror the inflammatory status of donor cells and modulate the inflammatory phenotype of recipient microglia and other cell types. ResultsWe demonstrated that intranasal administration of EVs derived from microglial-like BV2 cells to late adult mice (16–20 months of age) shifts microglia toward a “juvenile” morphology affecting their inflammatory profile. Mice treated with BV2-derived EVs have a reduction of anxiety-like behavior and an increased spatial learning, with sex-dependent differences. Further, BV2-derived EVs increased neuronal plasticity both in male and female mice. These findings suggest the involvement of microglial cells in vesicles-mediated anti-aging effect. ConclusionsOur data indicate that BV2-derived EVs could represent a resource to slow down age-dependent inflammation in the mouse brain.

Modulation of anxiety-like behavior in galactooligosaccharide-fed mice: A potential role for bacterial tryptophan metabolites and reduced microglial reactivity

Prebiotic galactooligosaccharides (GOS) reduce anxiety-like behaviors in mice and humans. However, the biological pathways behind these behavioral changes are not well understood. To begin to study these pathways, we utilized C57BL/6 mice that were fed a standard diet with or without GOS supplementation for 3 weeks prior to testing on the open field. After behavioral testing, colonic contents and serum were collected for bacteriome (16S rRNA gene sequencing, colonic contents only) and metabolome (UPLC-MS, colonic contents and serum data) analyses. As expected, GOS significantly reduced anxiety-like behavior (i.e., increased time in the center) and decreased cytokine gene expression (Tnfa and Ccl2) in the prefrontal cortex. Notably, time in the center of the open field was significantly correlated with serum methyl-indole-3-acetic acid (methyl-IAA). This metabolite is a methylated form of indole-3-acetic acid (IAA) that is derived from bacterial metabolism of tryptophan. Sequencing analyses showed that GOS significantly increased Lachnospiraceae UCG006 and Akkermansia; these taxa are known to metabolize both GOS and tryptophan. To determine the extent to which methyl-IAA can affect anxiety-like behavior, mice were intraperitoneally injected with methyl-IAA. Mice given methyl-IAA had a reduction in anxiety-like behavior in the open field, along with lower Tnfa in the prefrontal cortex. Methyl-IAA was also found to reduce TNF-α (as well as CCL2) production by LPS-stimulated BV2 microglia. Together, these data support a novel pathway through which GOS reduces anxiety-like behaviors in mice and suggests that the bacterial metabolite methyl-IAA reduces microglial cytokine and chemokine production, which in turn reduces anxiety-like behavior.

Serine racemase deletion alters adolescent social behavior and whole-brain cFos activation.

Neurodevelopmental disorders (NDDs) can cause debilitating impairments in social cognition and aberrant functional connectivity in large-scale brain networks, leading to social isolation and diminished everyday functioning. To facilitate the treatment of social impairments, animal models of NDDs that link N- methyl-D-aspartate receptor (NMDAR) hypofunction to social deficits in adulthood have been used. However, understanding the etiology of social impairments in NDDs requires investigating social changes during sensitive windows during development. We examine social behavior during adolescence using a translational mouse model of NMDAR hypofunction (SR-/-) caused by knocking out serine racemase (SR), the enzyme needed to make D-serine, a key NMDAR coagonist. Species-typical social interactions are maintained through brain-wide neural activation patterns; therefore, we employed whole-brain cFos activity mapping to examine network-level connectivity changes caused by SR deletion. In adolescent SR-/- mice, we observed disinhibited social behavior toward a novel conspecific and rapid social habituation toward familiar social partners. SR-/- mice also spent more time in the open arm of the elevated plus maze which classically points to an anxiolytic behavioral phenotype. These behavioral findings point to a generalized reduction in anxiety-like behavior in both social and non-social contexts in SR-/- mice; importantly, these findings were not associated with diminished working memory. Inter-regional patterns of cFos activation revealed greater connectivity and network density in SR-/- mice compared to controls. These results suggest that NMDAR hypofunction - a potential biomarker for NDDs - can lead to generalized behavioral disinhibition in adolescence, potentially arising from disrupted communication between and within salience and default mode networks.

Network pharmacology combined with molecular docking and experimental verification to elucidate the effect of flavan-3-ols and aromatic resin on anxiety

This study investigated the potential anxiolytic properties of flavan-3-ols and aromatic resins through a combined computational and experimental approach. Network pharmacology techniques were utilized to identify potential anxiolytic targets and compounds by analyzing protein–protein interactions and KEGG pathway data. Molecular docking and simulation studies were conducted to evaluate the binding interactions and stability of the identified targets. Behavioral tests, including the elevated plus maze test, open field test, light–dark test, actophotometer, and holeboard test, were used to assess anxiolytic activity. The compound-target network analysis revealed complex interactions involving 306 nodes and 526 edges, with significant interactions observed and an average node degree of 1.94. KEGG pathway analysis highlighted pathways such as neuroactive ligand-receptor interactions, dopaminergic synapses, and serotonergic synapses as being involved in anxiety modulation. Docking studies on EGCG (Epigallocatechin gallate) showed binding energies of −9.5 kcal/mol for MAOA, −9.2 kcal/mol for SLC6A4, and −7.4 kcal/mol for COMT. Molecular dynamic simulations indicated minimal fluctuations, suggesting the formation of stable complexes between small molecules and proteins. Behavioral tests demonstrated a significant reduction in anxiety-like behavior, as evidenced by an increased number of entries into and time spent in the open arm of the elevated plus maze test, light–dark test, open field center activity, hole board head dips, and actophotometer beam interruptions (p < 0.05 or p < 0.01). This research provides a comprehensive understanding of the multi-component, multi-target, and multi-pathway intervention mechanisms of flavan-3-ols and aromatic resins in anxiety treatment. Integrated network and behavioral analyses collectively support the anxiolytic potential of these compounds and offer valuable insights for future research in this area.

Effect of Probiotic Lacticaseibacillus rhamnosus LB1.5 on Anxiety-like Behavior, Neuroprotection and Neuroinflammation Markers of Male Mice Fed a High-Fat Diet.

Probiotic supplementation has been identified as a potential target to reduce inflammatory mediators associated with obesity. Therefore, this study assessed the effect of probiotic Lacticaseibacillus rhamnosus LB1.5 on anxiety-like behavior, gene expression in the prefrontal cortex, and neuroinflammation in the cerebral cortex and hippocampus of male mice fed a high-fat diet. Mice aged 21 days were divided into four groups: control (CONT), control plus probiotic (CONT + PROB), high-fat diet (HFD), and high-fat diet plus probiotic (HFD + PROB), and fed for 13 weeks. The probiotic Lact. rhamnosus 1.5 (3.1 × 108 CFU/mL, derived from raw buffalo milk) was administered by gavage three times a week. Probiotic supplementation provided an anxiolytic effect in CONT and HFD. The IL-6 showed lower levels after probiotic supplementation in the HFD. Regarding immunoreactivity for GFAP in the cerebral cortex, we demonstrated that animals HFD-fed had a reduction in cells number compared to CONT. In the hippocampus, we found an interaction between diet and supplementation, as well as an effect of probiotic supplementation. A higher number of Th positive cells was observed in the cerebral cortex in mice fed HFD. Lact. rhamnosus LB1.5 supplementation decreased serum IL-6 levels in HFD-fed mice and promoted a reduction in anxiety-like behavior.

Efficacy of Hot Tea Infusion vs. Ethanolic Extract of Moringa oleifera for the Simultaneous Treatment of Nonalcoholic Fatty Liver, Hyperlipidemia, and Hyperglycemia in a Murine Model Fed with a High-Fat Diet.

Moringa oleifera (MO) is a native tree of Asia and is cultivated in some areas of Mexico as part of traditional horticulture. The aim of the present study was to compare the efficacy of MO infusion vs. MO ethanolic extract for the simultaneous treatment of nonalcoholic fatty liver (NAFLD), hyperlipidemia, and hyperglycemia in a murine model fed with a high-fat diet (HFD). BALB/c mice were fed a balanced diet (healthy control) or an HFD for 6 months. With this, the NAFLD model was established before starting a therapeutic intervention with MO for two months. The phytochemical analysis by nuclear magnetic resonance in 1H and 13C experiments showed signals for pyrrole alkaloids and triterpenes as the main constituents of the extract and infusion preparation. A significant reduction of SGPT, SGOT, lipids, urea, and glucose in blood among NAFLD groups treated with MO (infusion or extract) was found, when compared to the NAFLD-placebo group. Steatosis and liver inflammation were found to be decreased in the MO groups, as infusion or ethanolic extract. Infusion produced a better therapeutic effect than the extract in all parameters, except glycemic control, where the extract was better. As an additional finding, it is noteworthy that treatment with MO, particularly through infusion, resulted in improved motor activity. Moreover, a reduction in anxiety-like behavior was observed exclusively with the administration of infusion. These observations provide valuable insights into the potential broader effects of Moringa oleifera beyond the primary aim of the study.

Impairments of cerebellar structure and function in a zebrafish KO of neuropsychiatric risk gene znf536

Genetic variants in ZNF536 contribute to the risk for neuropsychiatric disorders such as schizophrenia, autism, and others. The role of this putative transcriptional repressor in brain development and function is, however, largely unknown. We generated znf536 knockout (KO) zebrafish and studied their behavior, brain anatomy, and brain function. Larval KO zebrafish showed a reduced ability to compete for food, resulting in decreased total body length and size. This phenotype can be rescued by segregating the homozygous KO larvae from their wild-type and heterozygous siblings, enabling studies of adult homozygous KO animals. In adult KO zebrafish, we observed significant reductions in anxiety-like behavior and social interaction. These znf536 KO zebrafish have decreased cerebellar volume, corresponding to decreased populations of specific neuronal cells, especially in the valvular cerebelli (Va). Finally, using a Tg[mbp:mgfp] line, we identified a previously undetected myelin structure located bilaterally within the Va, which also displayed a reduction in volume and disorganization in KO zebrafish. These findings indicate an important role for ZNF536 in brain development and implicate the cerebellum in the pathophysiology of neuropsychiatric disorders.

Crosstalk between short- and long-term calorie restriction transcriptomic signatures with anxiety-like behavior, aging, and neurodegeneration: implications for drug repurposing

Calorie restriction (CR) is considered an effective intervention for anxiety, aging, and obesity. We investigated the effects of short- and long-term CR on behavior as well as transcriptome profiles in the hypothalamus, amygdala, prefrontal cortex, pituitary, and adrenal glands of Hooded Wistar and Long Evans male rats. A reduction in anxiety-like behavior, as assessed via the elevated plus maze, was observed in both short- and long-term CR. Despite this, short- and long-term CR regulated different sets of genes, leading to distinct transcriptomic signatures. The employed models were able to simultaneously analyze categorical and numerical variables, evaluating the effect of tissue type along with expression data. In all tissues, transcription factors, zinc finger protein 45-like and zinc finger BTB domain-containing two, were the top selected genes by the models in short and long-term CR treatments, respectively. Text mining identified associations between genes of the short-term CR signature and neurodegeneration, stress, and obesity and between genes of the long-term signature and the nervous system. Literature mining-based drug repurposing showed that alongside known CR mimetics such as resveratrol and rapamycin, candidates not typically associated with CR mimetics may be repurposed based on their interaction with transcriptomic signatures of CR. This study goes some way to unravelling the global effects of CR and opens new avenues for treatment for emotional disorders, neurodegeneration, and obesity.

Acute Ethanol Modulates Synaptic Inhibition in the Basolateral Amygdala via Rapid NLRP3 Inflammasome Activation and Regulates Anxiety-Like Behavior in Rats.

Chronic alcohol exposure leads to a neuroinflammatory response involving activation of the nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasome and proinflammatory cytokine production. Acute ethanol (EtOH) exposure activates GABAergic synapses in the central and basolateral amygdala (BLA) ex vivo, but whether this rapid modulation of synaptic inhibition is because of an acute inflammatory response and alters anxiety-like behavior in male and female animals is not known. Here, we tested the hypotheses that acute EtOH facilitates inhibitory synaptic transmission in the BLA by activating the NLRP3 inflammasome-dependent acute inflammatory response, that the alcohol-induced increase in inhibition is cell type and sex dependent, and that acute EtOH in the BLA reduces anxiety-like behavior. Acute EtOH application at a binge-like concentration (22-44 mm) stimulated synaptic GABA release from putative parvalbumin (PV) interneurons onto BLA principal neurons in ex vivo brain slices from male, but not female, rats. The EtOH facilitation of synaptic inhibition was blocked by antagonists of the Toll-like receptor 4 (TLR4), the NLRP3 inflammasome, and interleukin-1 receptors, suggesting it was mediated by a rapid local neuroinflammatory response in the BLA. In vivo, bilateral injection of EtOH directly into the BLA produced an acute concentration-dependent reduction in anxiety-like behavior in male but not female rats. These findings demonstrate that acute EtOH in the BLA regulates anxiety-like behavior in a sex-dependent manner and suggest that this effect is associated with presynaptic facilitation of parvalbumin-expressing interneuron inputs to BLA principal neurons via a local NLRP3 inflammasome-dependent neuroimmune response.SIGNIFICANCE STATEMENT Chronic alcohol exposure produces a neuroinflammatory response, which contributes to alcohol-associated pathologies. Acute alcohol administration increases inhibitory synaptic signaling in the brain, but the mechanism for the rapid alcohol facilitation of inhibitory circuits is unknown. We found that acute ethanol at binge-like concentrations in the basolateral amygdala (BLA) facilitates GABA release from parvalbumin-expressing (PV) interneuron synapses onto principal neurons in ex vivo brain slices from male rats and that intra-BLA ethanol reduces anxiety-like behavior in vivo in male rats, but not female rats. The ethanol (EtOH) facilitation of inhibition in the BLA is mediated by Toll-like receptor 4 (TLR4) and nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasome activation and proinflammatory IL-1β signaling, which suggests a rapid NLRP3 inflammasome-dependent neuroimmune cascade that plays a critical role in acute alcohol intoxication.

Fear extinction induced by activation of PKA ameliorates anxiety-like behavior in PTSD mice

Prolonged exposure (PE) therapy aiming to promote fear extinction is a useful treatment for post-traumatic stress disorder (PTSD). However, the mechanisms underlying fear extinction and effective methods used to promote fear extinction in PTSD are still lacking. In this study, we displayed dysfunctions of cyclic adenosine 3,5-monophosphate (cAMP)-protein kinase A (PKA), protein kinase B (Akt)/mammalian target of rapamycin (mTOR) and calcium signaling in peripheral serum of PTSD patients using bioinformatics analysis. Later, we confirmed the dysfunctions of cAMP-PKA, AKT/mTOR and calcium signaling in the hippocampus of PTSD mice. Moreover, the reduction of calpain1 in the hippocampus enhanced fear memory acquisition. Single activation of PKA by systemic application of rolipram (ROL) or meglumine cyclic adenylate (M-cAMP) before re-exposure promoted fear extinction and improved anxiety-like behavior in PTSD mice. Moreover, systemic application of ROL before re-exposure improved hippocampal brain-derived neurotrophic factor (BDNF)/tyrosine kinase receptor B (TrkB) signaling and calpain1/AKT/mTOR signaling. Interestingly, the effects of activation of PKA could be partially blocked by TrkB antagonist, ANA-12 and mTOR inhibitor, RAPA. Finally, intranasal administration of ROL could also adjust the abnormality of fear memory and improve anxiety-like behaviors in PTSD mice. Collectively, activation of PKA could promote fear extinction, which correlated with the reduction of anxiety-like behavior. The mechanisms were related to the BDNF/TrkB and calpain1/AKT/mTOR signaling pathways. PKA activation might be a useful complementary therapy for PE in the symptom elimination of PTSD.

Almond intake during pregnancy in rats improved the cognitive performance of adult male offspring

ABSTRACT Background: Based on evidence there are accepted links among early nutrition, epigenetic processes, and cognitive performance. Almond as a nutritious food could exert neuroprotective effects and improve anxiety, learning, and memory. Methods: In the current study, female rats were fed with a diet containing 5% (w/w) almonds during the mating period (two days) and gestation period (21 consecutive days). Then, the effect of the almond diet on short-term memory (Y maze), anxiety (elevated plus maze), and stress adaptation (forced swimming test) were investigated in the adult male offspring. The hippocampus (HIP), prefrontal cortex (PFC), and amygdala (AMY) of offspring were collected, and the level of cyclic AMP response element-binding proteins (CREB), brain-derived neurotrophic factor (BDNF) was assessed by western blotting. Also, Monoamine oxidases (MAO)-A and B activity were evaluated via enzymatic assays. Results: Our results indicated that prenatal almond consumption improved memory, made a modest reduction in anxiety-like behavior, and increased stress adaptation in adult male offspring. Also, molecular assessments showed an increased level of CREB phosphorylation and BDNF in the HIP and PFC of the almond group, while the activity of MAO-A and MAO-B was inhibited by almond consumption in mentioned areas. Discussion: These findings introduce almonds as a beneficial diet during pregnancy, for improving short-term memory, stress adaptation, and cognitive performance in adult offspring.

MeCP2 haplodeficiency and early-life stress interaction on anxiety-like behavior in adolescent female mice

BackgroundEarly-life stress can leave persistent epigenetic marks that may modulate vulnerability to psychiatric conditions later in life, including anxiety, depression and stress-related disorders. These are complex disorders with both environmental and genetic influences contributing to their etiology. Methyl-CpG Binding Protein 2 (MeCP2) has been attributed a key role in the control of neuronal activity-dependent gene expression and is a master regulator of experience-dependent epigenetic programming. Moreover, mutations in the MECP2 gene are the primary cause of Rett syndrome and, to a lesser extent, of a range of other major neurodevelopmental disorders. Here, we aim to study the interaction of MeCP2 with early-life stress in variables known to be affected by this environmental manipulation, namely anxiety-like behavior and activity of the underlying neural circuits.MethodsUsing Mecp2 heterozygous and wild-type female mice we investigated the effects of the interaction of Mecp2 haplodeficiency with maternal separation later in life, by assessing anxiety-related behaviors and measuring concomitant c-FOS expression in stress- and anxiety-related brain regions of adolescent females. Moreover, arginine vasopressin and corticotropin-releasing hormone neurons of the paraventricular hypothalamic nucleus were analyzed for neuronal activation.ResultsIn wild-type mice, maternal separation caused a reduction in anxiety-like behavior and in the activation of the hypothalamic paraventricular nucleus, specifically in corticotropin-releasing hormone-positive cells, after the elevated plus maze. This effect of maternal separation was not observed in Mecp2 heterozygous females that per se show decreased anxiety-like behavior and concomitant decreased paraventricular nuclei activation.ConclusionsOur data supports that MeCP2 is an essential component of HPA axis reprogramming and underlies the differential response to anxiogenic situations later in life.

Effect of chronic sleep deprivation and sleep recovery on hippocampal CA3 neurons, spatial memory and anxiety-like behavior in rats

Sleep deprivation-induced degenerative changes in the brain lead to the impairment of memory, anxiety, and quality of life. Several studies have reported the effects of sleep deprivation on CA1 and dentate gyrus regions of the hippocampus; in contrast, there is less known about the impact of chronic sleep deprivation (CSD) and sleep recovery on CA3 neurons and behavior. Hence, the present study aimed to understand the effect of CSD and sleep recovery on hippocampal CA3 neurons and spatial memory, and anxiety-like behavior in rats. Sixty male rats (Sprague Dawley) were grouped as control, environmental control (EC), CSD, 5 days sleep recovery (CSD + 5D SR), and 21 days sleep recovery (CSD + 21D SR). CSD, CSD + 5D SR and, CSD + 21D SR group rats were sleep deprived for 21 days (18 h/day). After CSD, the CSD + 5D SR and CSD + 21D SR rats were sleep recovered for 5- and 21-days respectively. Oxidative stress, dendritic arborization of CA3 neurons, spatial memory, and anxiety-like behavior was assessed. Spatial memory, basal, and apical dendritic branching points/intersections in hippocampal CA3 neurons were reduced, and anxiety-like behavior and oxidative stress increased significantly in the CSD group compared to control (p < 0.001). The CSD + 21D SR showed a significant improvement in spatial memory, reduction in anxiety-like behavior, and oxidative stress when compared to the CSD group (p < 0.05). The basal and apical dendritic branching points/intersections in hippocampal CA3 neurons were increased after CSD + 21D SR, however, it was not significant (p > 0.05). Even though the CSD + 21D SR showed a significant improvement in all the parameters, it did not reach the control level. There was an improvement in all the parameters after CSD + 5D SR but this was not significant compared to the CSD group (p > 0.05). Overall results indicate that the CSD-induced impairment of spatial memory and anxiety-like behavior was associated with oxidative stress and reduced dendritic arborization of hippocampal CA3 neurons. The CSD + 21D SR significantly reduced the damage caused by CSD, but it was not sufficient to reach the control level.

Dopaminergic dysfunction in the 3xTg-AD mice model of Alzheimer\u2019s disease

Alzheimer’s disease (AD) is characterized by amyloid (Aβ) protein aggregation and neurofibrillary tangles accumulation, accompanied by neuroinflammation. With all the therapeutic attempts targeting these biomarkers having been unsuccessful, the understanding of early mechanisms involved in the pathology is of paramount importance. Dopaminergic system involvement in AD has been suggested, particularly through the appearance of dopaminergic dysfunction-related neuropsychiatric symptoms and an overall worsening of cognitive and behavioral symptoms. In this study, we reported an early dopaminergic dysfunction in a mouse model presenting both amyloid and Tau pathology. 3xTg-AD mice showed an increase of postsynaptic D2/3R receptors density in the striatum and D2/3-autoreceptors in SN/VTA cell bodies. Functionally, a reduction of anxiety-like behavior, an increase in locomotor activity and D2R hyper-sensitivity to quinpirole stimulation have been observed. In addition, microglial cells in the striatum showed an early inflammatory response, suggesting its participation in dopaminergic alterations. These events are observed at an age when tau accumulation and Aβ deposits in the hippocampus are low. Thus, our results suggest that early dopaminergic dysfunction could have consequences in behavior and cognitive function, and may shed light on future therapeutic pathways of AD.

Arhgap22 Disruption Leads to RAC1 Hyperactivity Affecting Hippocampal Glutamatergic Synapses and Cognition in Mice

Rho GTPases are a class of G-proteins involved in several aspects of cellular biology, including the regulation of actin cytoskeleton. The most studied members of this family are RHOA and RAC1 that act in concert to regulate actin dynamics. Recently, Rho GTPases gained much attention as synaptic regulators in the mammalian central nervous system (CNS). In this context, ARHGAP22 protein has been previously shown to specifically inhibit RAC1 activity thus standing as critical cytoskeleton regulator in cancer cell models; however, whether this function is maintained in neurons in the CNS is unknown. Here, we generated a knockout animal model for arhgap22 and provided evidence of its role in the hippocampus. Specifically, we found that ARHGAP22 absence leads to RAC1 hyperactivity and to an increase in dendritic spine density with defects in synaptic structure, molecular composition, and plasticity. Furthermore, arhgap22 silencing causes impairment in cognition and a reduction in anxiety-like behavior in mice. We also found that inhibiting RAC1 restored synaptic plasticity in ARHGAP22 KO mice. All together, these results shed light on the specific role of ARHGAP22 in hippocampal excitatory synapse formation and function as well as in learning and memory behaviors.

GABA in the medial prefrontal cortex regulates anxiety-like behavior during the postpartum period

The postpartum period is commonly accompanied by emotional changes, which for many new mothers includes a reduction in anxiety. Previous research in rodents has shown that the postpartum attenuation in anxiety is dependent on offspring contact and has further implicated enhanced GABAergic neurotransmission as an underlying mechanism. However, the specific brain regions where GABA acts to regulate the offspring-induced reduction in postpartum anxiety requires further investigation. Here, we test the hypothesis that offspring interactions suppress anxiety-like behavior in postpartum female rats via GABA signaling in the medial prefrontal cortex (mPFC). Our results show a postpartum reduction in anxiety-like behavior, an effect which was abolished by localized infusion of the GABAA receptor antagonist bicuculline in the mPFC. We also show that activation of GABAA receptors in the mPFC by the agonist muscimol was effective in restoring anxiolyisis in mothers separated from their pups. Lastly, we show that heightened anxiety-like behavior in pup-separated mothers was accompanied by a lower number and percentage of activated GABAergic neurons within the mPFC. Together, these results suggest that mother-offspring interactions reduce anxiety-like behavior in postpartum females via GABAA neurotransmission in the mPFC and in doing so provide insight into mechanisms that may become dysfunctional in mothers who experience high postpartum anxiety.

Comprehensive Behavioral Phenotyping of a 16p11.2 Del Mouse Model for Neurodevelopmental Disorders.

The microdeletion of copy number variant 16p11.2 is one of the most common genetic mutations associated with neurodevelopmental disorders, such as Autism Spectrum Disorders (ASDs). Here, we describe our comprehensive behavioral phenotyping of the 16p11.2 deletion line developed by Alea Mills on a C57BL/6J and 129S1/SvImJ F1 background (Delm ). Male and female Delm mice were tested in developmental milestones as preweanlings (PND2-PND12), and were tested in open field activity, elevated zero maze, rotarod, novel object recognition, fear conditioning, social approach, and other measures during post-weaning (PND21), adolescence (PND42), and adulthood (>PND70). Developmentally, Delm mice show distinct weight reduction that persists into adulthood. Delm males also have reduced grasp reflexes and limb strength during development, but no other reflexive deficits whereas Delm females show limb strength deficits and decreased sensitivity to heat. In a modified version of a rotarod task that measures balance and coordinated motor activity, Delm males, but not females, show improved performance at high speeds. Delm males and females also show age-specific reductions in anxiety-like behavior compared with WTs, but neither sex show deficits in a social preference task. When assessing learning and memory, Delm males and females show age-specific impairments in a novel object or spatial object recognition, but no deficits in contextual fear memory. This work extends the understanding of the behavioral phenotypes seen with 16p11.2 deletion by emphasizing age and sex-specific deficits; important variables to consider when studying mouse models for neurodevelopmental disorders. LAY SUMMARY: Autism spectrum disorder is a common neurodevelopmental disorder that causes repetitive behavior and impairments in social interaction and communication. Here, we assess the effects of one of the most common genetic alterations in ASDs, a deletion of one copy of 29 genes, using a mouse model. These animals show differences in behavior between males and females and across ages compared with control animals, including changes in development, cognition, and motor coordination. Autism Res 2020, 13: 1670-1684. © 2020 International Society for Autism Research and Wiley Periodicals LLC.

Overexpression of neuropeptide Y decreases responsiveness to neuropeptide Y

Neuropeptide Y (NPY) is an endogenous neuropeptide that is abundantly expressed in the central nervous system. NPY is involved in various neurological processes and neuropsychiatric disorders, including fear learning and anxiety disorders. Reduced levels of NPY are reported in Post-Traumatic Stress Disorder (PTSD) patients, and NPY has been proposed as a potential therapeutic target for PTSD. It is therefore important to understand the effects of chronic enhancement of NPY on anxiety and fear learning. Previous studies have shown that acute elevation of NPY reduces anxiety, fear learning and locomotor activity. Models of chronic NPY overexpression have produced mixed results, possibly caused by ectopic NPY expression. NPY is expressed primarily by a subset of GABAergic interneurons, providing specific spatiotemporal release patterns. Administration of exogenous NPY throughout the brain, or overexpression in cells that do not normally release NPY, can have detrimental side effects, including memory impairment. In order to determine the effects of boosting NPY only in the cells that normally release it, we utilized a transgenic mouse line that overexpresses NPY only in NPY+ cells. We tested for effects on anxiety related behaviors in adolescent mice, an age with high incidence of anxiety disorders in humans. Surprisingly, we did not observe the expected reduction in anxiety-like behavior in NPY overexpression mice. There was no change in fear learning behavior, although there was a deficit in nest building. The effect of exogenous NPY on synaptic transmission in acute hippocampal slices was also diminished, indicating that the function of NPY receptors is impaired. Reduced NPY receptor function could contribute to the unexpected behavioral outcomes. We conclude that overexpression of NPY, even in cells that normally express it, can lead to reduced responsiveness of NPY receptors, potentially affecting the ability of NPY to function as a long-term therapeutic.

Lithium acts to modulate abnormalities at behavioral, cellular, and molecular levels in sleep deprivation-induced mania-like behavior.

Ample amount of data suggests role of rapid eye movement (REM) sleep deprivation as the cause and effect of mania. Studies have also suggested disrupted circadian rhythms contributing to the pathophysiology of mood disorders, including bipolar disorder. However, studies pertaining to circadian genes and effect of lithium treatment on clock genes are scant. Thus, we wanted to determine the effects of REM sleep deprivation on expression of core clock genes and determine whether epigenetics is involved. Next, we wanted to explore ultrastructural abnormalities in the hippocampus. Moreover, we were interested to determine oxidative stress, tumor necrosis factor-α (TNF-α), and brain-derived neurotrophic factor levels in the central and peripheral systems. Rats were sleep deprived by the flower pot method and were then analyzed for various behaviors and biochemical tests. Lithium was supplemented in diet. We found that REM sleep deprivation resulted in hyperactivity, reduction in anxiety-like behavior, and abnormal dyadic social interaction. Some of these behaviors were sensitive to lithium. REM sleep deprivation also altered circadian gene expression and caused significant imbalance between histone acetyl transferase/histone deacetylase (HAT/HDAC) activity. Ultrastructural analysis revealed various cellular abnormalities. Lipid peroxidation and increased TNF-α levels suggested oxidative stress and ongoing inflammation. Circadian clock genes were differentially modulated with lithium treatment and HAT/HDAC imbalance was partially prevented. Moreover, lithium treatment prevented myelin fragmentation, disrupted vasculature, necrosis, inflammation, and lipid peroxidation, and partially prevented mitochondrial damage and apoptosis. Taken together, these results suggest plethora of abnormalities in the brain following REM sleep deprivation, many of these changes in the brain may be target of lithium's mechanism of action.

Abstract P3007: Effect of Anti-Hypertensive Treatment Lisinopril on Central Arterial Stiffness and Anxiety-Like Behavior in Adult Hypertensive Dahl Salt-Sensitive Rats

Background: Independent of a high salt intake, Dahl Salt-Sensitive (DSS) rats demonstrate an age-associated increase in blood pressure (BP), and central arterial stiffness estimated by pulse wave velocity (PWV) accompanied by cognitive decline. We hypothesized, that anti-hypertensive treatment Lisinopril, in addition to BP decrease, will lower PWV and improve cognition of adult DSS. Methods: Twenty 6-mo old male DSS were kept on normal salt diet for the duration of the study; ten of them were continuously treated with Lisinopril (15 mg/kg/day) for 3 months. Systolic BP (SBP) and PWV (by doppler echocardiography) were measured, and open field test (OFT) was performed to assess locomotor and anxiety-like behavior at baseline prior to treatment and repeated in 3 months in 9-mo old rats. In a sub-cohort of DSS rats SBP was measured in 3-mo-old DSS. The data are presented as mean ± standard deviation and analyzed by 2-way ANOVA and T-test. Results: Prior to treatment, all DSS rats displayed hypertension and BP elevation with age (SBP: 170±11 vs. 142±5 mmHg, 6-mo vs. 3-mo; P&lt;0.01). After 3 months, control untreated animals showed no difference in SBP and were hypertensive. Rats treated with Lisinopril for 3 months showed a decreased SBP (119±9 vs. 171±11 mmHg, P&lt;0.0001) and a decreased PWV compared to their baseline prior to treatment (3.03±1.23 vs. 5.52±1.07 m/s p&lt;0.05). In OFT, treatment with Lisinopril increased exploration of the center of the field compared to the control group (120±35 vs. 87±30% of distance traveled in center to baseline , p=0.05) without affecting total distance traveled, indicating a reduction in anxiety-like behavior. Conclusion: Lowering of BP and PWV is associated with reduced anxiety-like behavior in DSS, which indicate the connection of cardiovascular disorder and cognitive function in adult hypertensive DSS. Whether Lisinopril has an additional direct effect on brain structure and function in DSS rats will be further studied. This research was supported entirely by the Intramural research Program of the NIH, National institute on Aging