Paneth Cell Defects Induce Microbiota Dysbiosis in Mice and Promote Visceral Hypersensitivity.

BACKGROUND & AIMS: Separation of newborn rats from their mothers induces visceral hypersensitivity and impaired epithelial secretory cell lineages when they are adults. Little is known about the mechanisms by which maternal separation causes visceral hypersensitivity or its relationship with defects in epithelial secretory cell lineages. METHODS: We performed studies with C3H/HeN mice separated from their mothers as newborns and mice genetically engineered (Sox9flox/flox-vil-cre on C57BL/6 background) to have deficiencies in Paneth cells. Paneth cell deficiency was assessed by lysozyme staining of ileum tissues and lysozyme activity in fecal samples. When mice were 50 days old, their abdominal response to colorectal distension was assessed by electromyography. Fecal samples were collected and microbiota were analyzed using Gut Low-Density Array quantitative polymerase chain reaction. RESULTS: Mice with maternal separation developed visceral hypersensitivity and defects in Paneth cells, as reported from rats, compared with mice without maternal separation. Sox9flox/flox-vil-Cre mice also had increased visceral hypersensitivity compared with control littermate Sox9flox/flox mice. Fecal samples from mice with maternal separation and from Sox9flox/flox-vil-cre mice had evidence for intestinal dysbiosis of the microbiota, characterized by expansion of Escherichia coli. Daily gavage of conventional C3H/HeN adult mice with 109 commensal E coli induced visceral hypersensitivity. Conversely, daily oral administration of lysozyme prevented expansion of E coli during maternal separation and visceral hypersensitivity. CONCLUSIONS: Mice with defects in Paneth cells (induced by maternal separation or genetically engineered) have intestinal expansion of E coli leading to visceral hypersensitivity. These findings provide evidence that Paneth cell function and intestinal dysbiosis are involved in visceral sensitivity.

Postnatal stress is associated with impaired fear conditioning and extinction, and heightened hippocampal fibroblast growth factor 2, in mother rats.

Rats exposed to early-life maternal separation (MS) exhibit later alterations in fear conditioning and impairments in fear extinction. As MS creates long-lasting anxiety in the mother, the present study assessed the influence of MS on fear conditioning and extinction in mother rats. It also examined whether estrous cycle effects on extinction, which are robust in nulliparous rats, but abolished in primiparous rats, re-emerge after MS. Following parturition, pups were removed from their mothers for 3 h daily from postpartum day 2-14 (MS), or remained housed with their mothers (standard reared condition, SR). Pups were weaned at postpartum day 24, and three months later, mothers received fear conditioning, extinction training, and test for extinction recall over three days. Extinction training took place during Proestrus (high estradiol and progesterone) or Metestrus (low estradiol and progesterone). Similar to past findings in non-stressed mothers, estrous cycle was not associated with conditioned fear expression (indexed by fear responses at the start of extinction training) or extinction recall in either MS or SR mothers. However, MS mothers exhibited weaker conditioned fear expression and impaired extinction recall, relative to SR mothers. Hippocampal fibroblast growth factor-2, a neurotrophin involved in stress regulation and fear expression, was elevated in MS relative to SR mothers. These results indicate that postnatal stress has long-lasting consequences for neural and behavioral systems involved in fear learning and inhibition without altering the involvement of ovarian hormones in these processes.

Is social dispersal stressful? A study in male crested macaques (Macaca nigra).

In gregarious species, dispersal events represent one of the most dramatic changes in social life and environment an animal will experience during life due to increased predation risk, aggression from unfamiliar conspecifics and the lack of social support. However, little is known about how individuals respond physiologically to dispersal and whether this process is stressful for the individuals involved. We therefore studied the physiological stress response during dispersal in the crested macaque, a primate species in which males often change groups. Over a period of 14months and 14 dispersal events in 4 groups, we determined faecal glucocorticoid metabolite (FGCM) levels during the process of immigration into a new group and examined a variety of factors (e.g. male age, rank achieved, number of males in the group) potentially affecting FGCM levels during this process. We found that FGCM levels were significantly elevated in the first few days upon immigration, after which levels returned quickly to baseline. FGCM response levels upon immigration were significantly and positively influenced by the number of males in the group. The rank a male achieved upon immigration, aggression received, as well as the proximity to other males did not significantly influence FGCM levels. Our data confirm previous findings on other species demonstrating that in crested macaques immigration into a new social group is associated with an acute endocrine stress response. However, given that stress hormone levels remained elevated only for a short period of time, we do not expect males to experience high physiological costs during immigration. Given our limited knowledge on the physiological responses to dispersal in animals, this study contributes to our understanding of dispersal more generally, and particularly inter-individual differences in the stress response and the potential physiological costs associated with these.

Infant stranger fear trajectories predict anxious behaviors and diurnal cortisol rhythm during childhood.

Although a robust literature has linked stable, high levels of fear across childhood to increased risk for anxiety problems, less is known about alternative pathways to anxiety. We tested two putatively normative developmental pathways of early fearfulness for their distinct associations with behavioral (anxiety-related behaviors and symptoms) and biological (diurnal cortisol) markers of anxiety risk in middle childhood in a community-based sample (n = 107). Steeper increases in fear from 6 to 36 months predicted more parent-reported anxiety symptoms at age 8 years. In addition, children who exhibited steep increases in fear during infancy were overrepresented among children with diagnoses of separation anxiety disorder at age 8 years. Finally, we showed that steeper increases in fearfulness in infancy predicted flatter slopes of diurnal cortisol at age 8 years for girls. Thus, differences in stranger fear across infancy may indicate varying degrees of risk for anxious behaviors in later childhood.

Behavioural and biochemical changes in maternally separated Sprague-Dawley rats exposed to restraint stress.

Early life adversity has been associated with the development of various neuropsychiatric disorders in adulthood such as depression and anxiety. The aim of this study was to determine if stress during adulthood can exaggerate the depression-/anxiety-like behaviour observed in the widely accepted maternally separated (MS) Sprague-Dawley (SD) rat model of depression. A further aim was to determine whether the behavioural changes were accompanied by changes in hippocampal brain-derived neurotrophic factor (BDNF) and the protein profile of the prefrontal cortex (PFC). Depression-/anxiety-like behaviour was measured in the elevated plus maze, open field and forced swim test (FST) in the MS SD rats exposed to chronic restraint stress in adulthood. As expected, MS increased immobility of SD rats in the FST but restraint stress did not enhance this effect of MS on SD rats. A proteomic analysis of the PFC revealed a decrease in actin-related proteins in MS and non-separated rats subjected to restraint stress as well as a decrease in mitochondrial energy-related proteins in the stressed rat groups. Since MS during early development causes a disruption in the hypothalamic-pituitary-adrenal axis and long-term changes in the response to subsequent stress, it may have prevented restraint stress from exerting its effects on behaviour. Moreover, the decrease in proteins related to mitochondrial energy metabolism in MS rats with or without subsequent restraint stress may be related to stress per se and not depression-like behaviour, because rats subjected to restraint stress displayed similar decreases in energy-related proteins and spent less time immobile in the FST than control rats.

Perinatal Brain Injury is Accompanied by Disturbances in Expression of SLC Protein Superfamily in Endotheliocytes of Hippocampal Microvessels.

The peculiarities in expression of transport proteins and the proteins implicated in the control of glycolysis by the cellular components of neurovascular units were examined in animals of different age under normal conditions and after modeled perinatal stress or hypoxic brain injury. In both cases, the specialties in expression of transport proteins in ontogenesis were revealed. The perinatal hypoxic brain injury resulted in up-regulation of MCT1, MCT4, and GLUT4 expression in endotheliocytes of hippocampal microvessels accompanied by transient elevation of HIF-1α and GSK3 expression.

Cortisol regulation in 12-month-old human infants: associations with the infants' early history of breastfeeding and co-sleeping.

Experiences during early life are suggested to affect the physiological systems underlying stress responses, including the hypothalamic-pituitary-adrenal axis (HPA axis). While stressful early experiences have been associated with dysregulated HPA-axis functioning, positive early experiences, i.e. high maternal caregiving quality, contribute to more optimal HPA-axis functioning. Influences of other early caregiving factors, however, are less well documented. The goal of this study was to examine whether breastfeeding and co-sleeping during the first 6 months of life were associated with infant cortisol regulation, i.e. cortisol reactivity and recovery, to a stressor at 12 months of age. Participants were 193 infants and their mothers. Information on breastfeeding and co-sleeping was collected using weekly and daily sleep diaries, respectively, for the first 6 months of life. Co-sleeping was defined as sleeping in the parents' bed or sleeping in the parents' room. At 12 months of age, infants were subjected to a psychological stressor [Strange Situation Procedure (SSP); Ainsworth et al. 1978]. Salivary cortisol was measured prestressor and at 25, 40, and 60 min poststressor to measure reactivity and recovery. Regression analyses showed that after controlling for maternal sensitivity, infant attachment status, feeding, and sleeping arrangements at 12 months of age and other confounders, more weeks of co-sleeping predicted lower infant cortisol reactivity to the SSP. Also, more weeks of breastfeeding predicted quicker cortisol recovery. These results indicate that an early history of co-sleeping and breastfeeding contributes positively to cortisol regulation in 12-month-olds.

Controlled cross-over study in normal subjects of naloxone-preceding-lactate infusions; respiratory and subjective responses: relationship to endogenous opioid system, suffocation false alarm theory and childhood parental loss.

BACKGROUND: The expanded suffocation false alarm theory (SFA) hypothesizes that dysfunction in endogenous opioidergic regulation increases sensitivity to CO2, separation distress and panic attacks. In panic disorder (PD) patients, both spontaneous clinical panics and lactate-induced panics markedly increase tidal volume (TV), whereas normals have a lesser effect, possibly due to their intact endogenous opioid system. We hypothesized that impairing the opioidergic system by naloxone could make normal controls parallel PD patients' response when lactate challenged. Whether actual separations and losses during childhood (childhood parental loss, CPL) affected naloxone-induced respiratory contrasts was explored. Subjective panic-like symptoms were analyzed although pilot work indicated that the subjective aspect of anxious panic was not well modeled by this specific protocol. METHOD: Randomized cross-over sequences of intravenous naloxone (2 mg/kg) followed by lactate (10 mg/kg), or saline followed by lactate, were given to 25 volunteers. Respiratory physiology was objectively recorded by the LifeShirt. Subjective symptomatology was also recorded. RESULTS: Impairment of the endogenous opioid system by naloxone accentuates TV and symptomatic response to lactate. This interaction is substantially lessened by CPL. CONCLUSIONS: Opioidergic dysregulation may underlie respiratory pathophysiology and suffocation sensitivity in PD. Comparing specific anti-panic medications with ineffective anti-panic agents (e.g. propranolol) can test the specificity of the naloxone+lactate model. A screen for putative anti-panic agents and a new pharmacotherapeutic approach are suggested. Heuristically, the experimental unveiling of the endogenous opioid system impairing effects of CPL and separation in normal adults opens a new experimental, investigatory area.

Infant anticipatory stress.

In humans, anticipatory stress involves activation of the limbic-hypothalamic-pituitary-adrenal axis, which releases stress hormones such as cortisol in response to an impending stressor. Conditioning of the stress response to anticipate and prepare for future challenges is a hallmark of adaptation. It is unknown whether human infants in the first year of life have developed the neural circuitry to support the anticipation of stressful events in an attachment context. Here, we show that human infants at six months of age produce an anticipatory stress response, as indicated by the release of stress hormones, when re-exposed after 24 h to a context in which they demonstrated a stress response to a disruption in the parent-infant relationship. Although infant stress response (cortisol elevation) was greater to the stressful event (parent unresponsiveness) than to the second exposure to the stress context (room, chair, presence of parent and experimenter, etc.), it was greater in the stress group than in the control group on both days. Results suggest that human infants have the capacity to produce an anticipatory stress response that is based on expectations about how their parents will treat them in a specific context.

DNA methylation of Vesicular Glutamate Transporters in the mesocorticolimbic brain following early-life stress and adult ethanol exposure-an explorative study.

DNA methylation and gene expression can be altered by early life stress (ELS) and/or ethanol consumption. The present study aimed to investigate whether DNA methylation of the Vesicular Glutamate Transporters (Vglut)1-3 is related to previously observed Vglut1-3 transcriptional differences in the ventral tegmental area (VTA), nucleus accumbens (Acb), dorsal striatum (dStr) and medial prefrontal cortex (mPFC) of adult rats exposed to ELS, modelled by maternal separation, and voluntary ethanol consumption. Targeted next-generation bisulfite sequencing was performed to identify the methylation levels on 61 5'-cytosine-phosphate-guanosine-3' sites (CpGs) in potential regulatory regions of Vglut1, 53 for Vglut2, and 51 for Vglut3. In the VTA, ELS in ethanol-drinking rats was associated with Vglut1-2 CpG-specific hypomethylation, whereas bidirectional Vglut2 methylation differences at single CpGs were associated with ELS alone. Exposure to both ELS and ethanol, in the Acb, was associated with lower promoter and higher intronic Vglut3 methylation; and in the dStr, with higher and lower methylation in 26% and 43% of the analyzed Vglut1 CpGs, respectively. In the mPFC, lower Vglut2 methylation was observed upon exposure to ELS or ethanol. The present findings suggest Vglut1-3 CpG-specific methylation signatures of ELS and ethanol drinking, underlying previously reported Vglut1-3 transcriptional differences in the mesocorticolimbic brain.

Neonatal stress and attenuation of the hypercapnic ventilatory response in adult male rats: the role of carotid chemoreceptors and baroreceptors.

Neonatal maternal separation (NMS) is a form of stress that disrupts respiratory control development. Awake adult male rats previously subjected to NMS show a ventilatory response to hypercapnia (HCVR; Fi(CO(2)) = 0.05) 47% lower than controls; however, the underlying mechanisms are unknown. To address this issue, we first tested the hypothesis that carotid bodies contribute to NMS-related attenuation of the HCVR by using carotid sinus nerve section or Fi(O(2)) manipulation to maintain Pa(O(2)) constant (iso-oxic) during hypercapnic hyperpnea. We then determined whether NMS-related augmentation of baroreflex sensitivity contributes to the reduced HCVR in NMS rats. Nitroprusside and phenylephrine injections were used to manipulate arterial blood pressure in both groups of rats. Pups subjected to NMS were separated from their mother 3 h/day from postnatal days 3 to 12. Control rats were undisturbed. At adulthood, rats were anesthetized [urethane (1g/kg) + isoflurane (0.5%)], and diaphragmatic electromyogram (dEMG) was measured under baseline and hypercapnic conditions (Pa(CO(2)): 10 Torr above baseline). The relative minute activity response to hypercapnia of anesthetized NMS rats was 34% lower than controls. Maintaining Pa(O(2)) constant during hypercapnia reversed this phenotype; the HCVR of NMS rats was 45% greater than controls. Although the decrease in breathing frequency during baroreflex activation was greater in NMS rats, the change observed within the range of pressure change observed during hypercapnia was minimal. We conclude that NMS-related changes in carotid body sensitivity to chemical stimuli and/or its central integration is a key mechanism in the attenuation of HCVR by NMS.

Association between prolonged separation from parents and allostatic load among children in China.

OBJECTIVE: To capture the association of exposure to prolonged separation from both parents early in life and allostatic load (AL), a measure of biological multi-system dysregulation. METHODS: We used data from 557 7-12-year-old children enrolled in rural area of Chizhou city, Anhui Province, China. We computed an AL score based on eleven biomarkers representing four regulatory systems: immune/inflammatory system (high sensitivity C-reactive protein); metabolic system (body mass index; high density lipoprotein; low density lipoprotein, total cholesterol; triglycerides; fasting glucose; glycated hemoglobin; insulin) and cardiovascular system (systolic and diastolic blood pressure). Child's experiences of parent-child separation were collected a brief online questionnaire by parents of children. RESULTS: More than 1 in 3 of our participants separated with both parents at age 6 or younger and nearly 1 in 10 persistently separated from both parents after birth. The AL score was significantly higher among children separated from both parents during early childhood (3.25 ± 1.98) or persistently since birth (3.48 ± 1.92), compared with those who did not separated from both parents (2.34 ± 1.53, F = 12.992, P<0.001). After adjustment of demographic covariates, body mass index as well as parent frequency of communication and parental warmth, children who separated from both parents in early childhood (ß = 0.84, 95%CI:0.40, 1.28, P < 0.001) or persistently into adolescence (ß = 1.27, 95%CI:0.43, 2.12, P = 0.003) evinced the highest levels of AL. CONCLUSION: This study is the first to show an association between prolonged parent-child separation and physiological wear-and-tear as measured by AL, which provides potential insights into the biological mechanisms underpinning long-term health outcomes in contexts of parent-child separation.

AMBMP activates WNT pathway and alleviates stress-induced behaviors in maternal separation and chronic stress models.

Depressive disorders are both prevalent and debilitating, and a proportion of patients have treatment resistance to classic antidepressants. Recent evidence has implicated the intracellular WNT signaling pathway as having a key role in the pathogenesis of major depressive disorder. In the present study, we investigated the role of ß-catenin and transcription factor-4 (TCF4) in the depression-like and anxiety-like behaviors exhibited by mice exposed to maternal separation, or chronic mild stress. Both rodent models of childhood and adulthood stress showed depression and anxiety-like behaviors. During the last three weeks of medication, we applied AMBMP (2-Amino-4-[3,4- (methylenedioxy)benzylamino]-6-(3-methoxyphenyl)pyrimidine) to the maternal separation and chronic stress model for the first time. The drug alleviated the depression-like index in saccharin preference test (SPT) and forced swim test (FST), and anxiety-like index in open field test (OFT) and elevated-plus maze (EPM), and reversed the disruption of ß-catenin and TCF4 in stressed mice by upregulating the WNT pathway specifically. Therefore, the WNT pathway may be involved in the mediation of patient recovery and could be a target for novel antidepressants.

Maternal separation of rat pups increases the risk of developing depressive-like behavior after subsequent chronic stress by altering corticosterone and neurotrophin levels in the hippocampus.

Children that are abused have an increased risk for developing psychiatric disorders later in life, because of the negative effects of stress on the developing brain. We used a maternal separation model in rats to see how neurotrophins, stress hormones, behavior and the anti-oxidant potential of serum are affected. Rat pups were separated from their mothers for 3h/day on days 2-14. Maternal separation caused changes in levels of NGF and NT-3 in the dorsal and ventral hippocampus, increased basal corticosterone levels and decreased ACTH levels after acute restraint stress. The anti-oxidant potential of the rat serum was significantly lower in the maternal separation group. Depressive-like behavior, measured during a forced swim test, was seen in maternally separated rats after additional chronic stress during adulthood. Maternal separation caused downregulation of neurotrophins in the ventral hippocampus, possibly as an effect of high corticosterone levels, but compensatory mechanisms against cell death may be involved as neurotrophin levels increased in the dorsal hippocampus. Decreased anti-oxidant potential of serum could have been an effect of downregulated neurotrophin levels.

Panic, suffocation false alarms, separation anxiety and endogenous opioids.

This review paper presents an amplification of the suffocation false alarm theory (SFA) of spontaneous panic [Klein DF (1993). False suffocation alarms, spontaneous panics, and related conditions. An integrative hypothesis. Arch Gen Psychiatry; 50:306-17.]. SFA postulates the existence of an evolved physiologic suffocation alarm system that monitors information about potential suffocation. Panic attacks maladaptively occur when the alarm is erroneously triggered. That panic is distinct from Cannon's emergency fear response and Selye's General Alarm Syndrome is shown by the prominence of intense air hunger during these attacks. Further, panic sufferers have chronic sighing abnormalities outside of the acute attack. Another basic physiologic distinction between fear and panic is the counter-intuitive lack of hypothalamic-pituitary-adrenal (HPA) activation in panic. Understanding panic as provoked by indicators of potential suffocation, such as fluctuations in pCO(2) and brain lactate, as well as environmental circumstances fits the observed respiratory abnormalities. However, that sudden loss, bereavement and childhood separation anxiety are also antecedents of "spontaneous" panic requires an integrative explanation. Because of the opioid system's central regulatory role in both disordered breathing and separation distress, we detail the role of opioidergic dysfunction in decreasing the suffocation alarm threshold. We present results from our laboratory where the naloxone-lactate challenge in normals produces supportive evidence for the endorphinergic defect hypothesis in the form of a distress episode of specific tidal volume hyperventilation paralleling challenge-produced and clinical panic.

Platelet 18 kDa Translocator Protein density is reduced in depressed patients with adult separation anxiety.

RATIONALE: Recent studies indicate that Adult Separation Anxiety Disorder (ASAD) may represent a discrete diagnostic entity worthy of attention. Adults with separation anxiety report extreme anxiety and fear about separations from major attachment figures (partner, children or parents). These symptoms affect individual's behavior, lead to severe impairment in social relationships and are not better accounted for by the presence of agoraphobia. In a previous study we found platelet expression reduction of the 18 kDa Translocator Protein (TSPO) (the new nomenclature for the peripheral-type benzodiazepine receptor) in patients with panic disorder who also fulfilled the diagnostic criteria for ASAD. OBJECTIVES: To explore whether separation anxiety might be a factor differentiating TSPO expression in a sample of patients with major depression. METHODS: The equilibrium binding parameters of the specific TSPO ligand [3H]PK 11195 were estimated on platelet membranes from 40 adult outpatients with DSM-IV diagnosis of MDD, with or without separation anxiety symptoms, and 20 healthy controls. Patients were assessed by SCID-I, HAM-D, the Structured Clinical Interview for Separation Anxiety Symptoms (SCI-SAS-A) and the Adult Separation Anxiety Self-report Checklist (ASA-27). RESULTS: A significant reduction of platelet TSPO density mean value was found in depressed patients with associated ASAD symptoms, while no significant differences were found between depressed patients without ASAD and the control group. Individual TSPO density values were significantly and negatively correlated with both SCI-SAS-A and ASA-27 total scores, but not with HAM-D total score or HAM-D anxiety/somatization factor score. CONCLUSIONS: The reduction of platelet TSPO density in our sample of patients with depression was specifically related to the presence of ASAD. These data suggest that TSPO expression evaluation is a useful biological marker of ASAD.

Effects of early life stress on [11C]DASB positron emission tomography imaging of serotonin transporters in adolescent peer- and mother-reared rhesus monkeys.

Peer-reared (PR) rhesus monkeys with early maternal separation later exhibit aggressiveness, impaired impulse control, alcohol abuse, and low CSF 5-hydroxyindoleacetic acid. This study compared regional brain serotonin transporter (SERT) binding between nine PR and seven mother-reared rhesus monkeys with [11C]DASB positron emission tomography (PET) imaging. Parametric images of binding potential (BP) (which is proportional to Bmax/KD, in which Bmax is transporter density and KD is dissociation constant) and relative blood flow (R1) were generated by the two-parameter multilinear reference tissue model. R1 images were used for coregistration and normalization of PET parametric data to the magnetic resonance imaging template space. Group BP differences were analyzed voxelwise by Student's t test in SPM2. Region of interest-based parameter values were also calculated to obtain the magnitude of regional BP differences between the two groups. For the PR group, SERT BP was decreased by 10-23% across a range of brain areas consisting of the raphe, thalamus, hypothalamus, caudate and putamen, globus pallidum, anterior cingulate gyrus, and medial temporal regions, including amygdala and hippocampus (cluster-level corrected p = 0.002). For the latter three regions, BP was decreased in the right hemisphere. These results agree with the hypothesis that early maternal deprivation affects the development of the serotonergic system and suggest that decreased serotonergic innervations in the critical brain regions may explain some of the behavioral and biochemical abnormalities in PR monkeys.

Anxiolytic-like properties of the anandamide transport inhibitor AM404.

The endocannabinoids anandamide and 2-arachidonoyglycerol (2-AG) may contribute to the regulation of mood and emotion. In this study, we investigated the impact of the endocannabinoid transport inhibitor AM404 on three rat models of anxiety: elevated plus maze, defensive withdrawal and separation-induced ultrasonic vocalizations. AM404 (1-5 mg kg(-1), intraperitoneal (i.p.)) exerted dose-dependent anxiolytic-like effects in the three models. These behavioral effects were associated with increased levels of anandamide, but not 2-AG, in the prefrontal cortex and were prevented by the CB(1) cannabinoid antagonist rimonabant (SR141716A), suggesting that they were dependent on anandamide-mediated activation of CB(1) cannabinoid receptors. We also evaluated whether AM404 might influence motivation (in the conditioned place preference (CPP) test), sensory reactivity (acoustic startle reflex) and sensorimotor gating (prepulse inhibition (PPI) of the startle reflex). In the CPP test, AM404 (1.25-10 mg kg(-1), i.p.) elicited rewarding effects in rats housed under enriched conditions, but not in rats kept in standard cages. Moreover, AM404 did not alter reactivity to sensory stimuli or cause overt perceptual distortion, as suggested by its lack of effect on startle or PPI of startle. These results support a role of anandamide in the regulation of emotion and point to the anandamide transport system as a potential target for anxiolytic drugs.

Salivary oxytocin in clinically anxious youth: Associations with separation anxiety and family accommodation.

Clinical anxiety disorders in youth are common and associated with interpersonal behaviors including reliance on parents for family accommodation, or changes that parents make to their own behaviors to help the youth avoid anxiety related distress. The neuropeptide oxytocin is associated with the regulation of anxiety and of close interpersonal behavior leading to the hypothesis that oxytocinergic functioning plays a role in youth anxiety and its disorders, and the resulting family accommodation. To test this hypothesis salivary OT from 50 youth with primary DSM-5 anxiety disorders was assayed. A multi-source/multi-method anxiety assessment including semistructured interviews with youth and mothers, rating scales, and behavioral observations was used to assess anxiety disorders and symptoms, and family accommodation. Youth with separation anxiety disorder had significantly lower salivary OT levels than clinically anxious youth not diagnosed with separation anxiety disorder. Salivary OT levels were significantly negatively correlated with separation anxiety symptoms based on both youth- and mother-ratings. Anxious behavior displayed by youth during interactions with their mothers was associated with lower salivary OT levels in youth. Maternal ratings of family accommodation were negatively associated with salivary OT levels in youth. Results support the role of the oxytocinergic system in youth anxiety and its disorders and in parental involvement in youth anxiety through family accommodation. OT may be particularly important for diagnoses and symptoms of separation anxiety, which is inherently interpersonal in nature. Findings have potentially important implications for assessment and treatment of anxiety in youth.

Histone Modifications in a Mouse Model of Early Adversities and Panic Disorder: Role for Asic1 and Neurodevelopmental Genes.

Hyperventilation following transient, CO2-induced acidosis is ubiquitous in mammals and heritable. In humans, respiratory and emotional hypersensitivity to CO2 marks separation anxiety and panic disorders, and is enhanced by early-life adversities. Mice exposed to the repeated cross-fostering paradigm (RCF) of interference with maternal environment show heightened separation anxiety and hyperventilation to 6% CO2-enriched air. Gene-environment interactions affect CO2 hypersensitivity in both humans and mice. We therefore hypothesised that epigenetic modifications and increased expression of genes involved in pH-detection could explain these relationships. Medullae oblongata of RCF- and normally-reared female outbred mice were assessed by ChIP-seq for H3Ac, H3K4me3, H3K27me3 histone modifications, and by SAGE for differential gene expression. Integration of multiple experiments by network analysis revealed an active component of 148 genes pointing to the mTOR signalling pathway and nociception. Among these genes, Asic1 showed heightened mRNA expression, coherent with RCF-mice's respiratory hypersensitivity to CO2 and altered nociception. Functional enrichment and mRNA transcript analyses yielded a consistent picture of enhancement for several genes affecting chemoception, neurodevelopment, and emotionality. Particularly, results with Asic1 support recent human findings with panic and CO2 responses, and provide new perspectives on how early adversities and genes interplay to affect key components of panic and related disorders.