Chromosome 4q31-34 panic disorder risk locus: association of neuropeptide Y Y5 receptor variants

Connecting genomic and proteomic signatures of amyloid burden in the brain

Background

Alzheimer's disease (AD) has a high heritable component characteristic of complex diseases, yet many of the genetic risk factors remain unknown. We combined genome-wide association studies (GWAS) on amyloid endophenotypes measured in cerebrospinal fluid (CSF) and positron emission tomography (PET) as surrogates of amyloid pathology, which may be helpful to understand the underlying biology of the disease.

Methods

We performed a meta-analysis of GWAS of CSF Aβ42 and PET measures combining six independent cohorts (n=2,076). Due to the opposite effect direction of Aβ phenotypes in CSF and PET measures, only genetic signals in the opposite direction were considered for analysis (n=376,599). Polygenic risk scores (PRS) were calculated and evaluated for AD status and amyloid endophenotypes. We then searched the CSF proteome signature of brain amyloidosis using SOMAscan proteomic data (Ace cohort, n=1,008) and connected it with GWAS results of loci modulating amyloidosis. Finally, we compared our results with a large meta-analysis using publicly available datasets in CSF (n=13,409) and PET (n=13,116). This combined approach enabled the identification of overlapping genes and proteins associated with amyloid burden and the assessment of their biological significance using enrichment analyses.

Results

After filtering the meta-GWAS, we observed genome-wide significance in the rs429358-APOE locus and nine suggestive hits were annotated. We replicated the APOE loci using the large CSF-PET meta-GWAS and identified multiple AD-associated genes as well as the novel GADL1 locus. Additionally, we found a significant association between the AD PRS and amyloid levels, whereas no significant association was found between any Aβ PRS with AD risk. CSF SOMAscan analysis identified 1,387 FDR-significant proteins associated with CSF Aβ42 levels. The overlap among GWAS loci and proteins associated with amyloid burden was very poor (n=35). The enrichment analysis of overlapping hits strongly suggested several signalling pathways connecting amyloidosis with the anchored component of the plasma membrane, synapse physiology and mental disorders that were replicated in the large CSF-PET meta-analysis.

Conclusions

The strategy of combining CSF and PET amyloid endophenotypes GWAS with CSF proteome analyses might be effective for identifying signals associated with the AD pathological process and elucidate causative molecular mechanisms behind the amyloid mobilization in AD.

Epistasis in neurotransmitter receptors linked to posttraumatic stress disorder and major depressive disorder comorbidity in traumatized Chinese

Background

Posttraumatic stress disorder (PTSD) and major depressive disorder (MDD) comorbidity occurs through exposure to trauma with genetic susceptibility. Neuropeptide-Y (NPY) and dopamine are neurotransmitters associated with anxiety and stress-related psychiatry through receptors. We attempted to explore the genetic association between two neurotransmitter receptor systems and the PTSD-MDD comorbidity.

Methods

Four groups were identified using latent profile analysis (LPA) to examine the patterns of PTSD and MDD comorbidity among survivors exposed to earthquake-related trauma: low symptoms, predominantly depression, predominantly PTSD, and PTSD-MDD comorbidity. NPY2R (rs4425326), NPY5R (rs11724320), DRD2 (rs1079597), and DRD3 (rs6280) were genotyped from 1,140 Chinese participants exposed to earthquake-related trauma. Main, gene-environment interaction (G × E), and gene-gene interaction (G × G) effects for low symptoms, predominantly depression, and predominantly PTSD were tested using a multinomial logistic model with PTSD-MDD comorbidity as a reference.

Results

The results demonstrated that compared to PTSD-MDD comorbidity, epistasis (G × G) NPY2R-DRD2 (rs4425326 × rs1079597) affects low symptoms (β = -0.66, OR = 0.52 [95% CI: 0.32-0.84], p = 0.008, pperm = 0.008) and predominantly PTSD (β = -0.56, OR = 0.57 [95% CI: 0.34-0.97], p = 0.037, pperm = 0.039), while NPY2R-DRD3 (rs4425326 × rs6280) impacts low symptoms (β = 0.82, OR = 2.27 [95% CI: 1.26-4.10], p = 0.006, pperm = 0.005) and predominantly depression (β = 1.08, R = 2.95 [95% CI: 1.55-5.62], p = 0.001, pperm = 0.001). The two G × G effects are independent.

Conclusion

NPY and dopamine receptor genes are related to the genetic etiology of PTSD-MDD comorbidity, whose specific mechanisms can be studied at multiple levels.

The neuropeptide Y single-nucleotide polymorphism rs16147:T>C moderates the effect of alcohol dependence on depression in male Chinese Han population

BACKGROUND

Previous studies suggest that alcohol dependence is associated with depression, however, the effect of alcohol dependence varies from individual to individual, which may be due to different genetic backgrounds. The interactions between alcohol dependence and different gene polymorphisms may finally shape the onset of depression. Neuropeptide Y (NPY), which can maintain homeostasis from high-stress stimulation, may protect individuals from the onset of depression. Here, we explored whether the NPY rs16147:T>C has an association with depression in individuals with alcohol dependence during the period of alcohol dependence withdrawal.

METHODS

A total of 455 males with alcohol dependence were recruited. The scale of Michigan Alcoholism Screening Test (MAST) and Self-Depression Scale (SDS) were respectively used to analyze the condition of alcohol dependence and depression. Genomic DNA was extracted from each blood sample and NPY polymorphisms were genotyped. The interaction between NPY rs16147:T>C and alcohol dependence on depression was first analyzed. Then, region of significance analysis was used to confirm which model provided the best fit for the interaction (diathesis-stress or differential susceptibility). Finally, by using internal replication analyses, the accuracy and robustness of the interaction results were improved.

RESULTS

Alcohol dependence was positively correlated with depression. CC homozygotes of NPY rs16147:T>C exhibited less depression when exposed to low alcohol dependence, but more depression when exposed to high alcohol dependence. Individuals with the T allele showed the opposite result.

CONCLUSION

NPY rs16147:T>C might be correlated with susceptibility for depression in males during alcohol dependence withdrawal. The findings support the differential susceptibility model.

[Effect of a Mediterranean-pattern diet on the metabolic response secondary to weight loss; role of the single nucleotide polymorphism (rs16147) of neuropeptide Y]

Introduction

Background and aims: intervention studies that evaluate the effect of rs16147 on metabolic response and weight change after dietary intervention are scarce. We propose to evaluate the role of the rs16147 genetic variant in the metabolic effects produced by a hypocaloric Mediterranean-pattern diet with high content of omega-9. Material and methods: a sample of 363 obese subjects was recruited. At the baseline visit the patients were randomly assigned to one of two hypocaloric diets for 12 weeks (diet M, Mediterranean pattern; diet C, standard hypocaloric). All patients, at baseline and at 12 weeks, had biochemical and anthropometric variables measured, and genotyping performed for the rs16147 variant. Results: in all subjects, and with both diets, the parameters of adiposity, blood pressure, and circulating leptin improved. In obese subjects with allele (A) insulin levels (GG vs. GA + AA) (-0.9 ± 1.1 IU/L vs. -4.4 ± 1.0 IU/L; p = 0.01) and HOMA-IR (-0.3 ± 0.1 units vs. -1.2 ± 0.3 units; p = 0.02) decreased significantly with diet M. Subjects carrying the minor allele showed a significant decrease in basal insulin levels (GG vs. GA + AA) (0.7 ± 0.3 IU/L vs. -2.2 ± 0.9 IU/L: p = 0.02) and HOMA-IR (-0.3 ± 0.2 units vs. -0.7 ± 0.1 units: p = 0.01) after diet C. This decrease in circulating insulin and HOMA-IR levels in patients with allele A was significantly higher with diet M than with diet C. Conclusions: the A allele of the rs16147 variant produces a better metabolic response in terms of insulin resistance and basal insulin secondary to weight loss with two different hypocaloric diets in obese subjects, with improvement being higher with the Mediterranean diet.

Different effects of high-protein/low-carbohydrate versus standard hypocaloric diet on insulin resistance and lipid profile: Role of rs16147 variant of neuropeptide Y

BACKGROUND AND AIMS

Few studies have assessed the effect of the NPY gene rs16147 variant on metabolic response following a dietary intervention. We evaluated the effect of rs16147 on body weight and biochemical changes after a high-protein/low-carbohydrate hypocaloric diet compared with a standard severe hypocaloric diet over 9 months.

MATERIALS AND METHODS

A population of 270 obese individuals was enrolled. At baseline, participants were randomly allocated to one of two hypocaloric diets, high protein (Diet HP) or standard (Diet S), for a period of 9 months.

RESULTS

After both diets, all genotypes showed decreased body mass index, weight, fat mass, waist circumference, and leptin levels. Participants with the minor allele (A) assigned to the HP diet showed decreases in total cholesterol (-6.5 ± 4.8 vs 10.1 ± 4.1 mg/dL; p < 0.05), LDL cholesterol (-5.9 ± 3.8 vs 9.6 ± 2.4 mg/dL; p < 0.05), triglycerides (-1.0 ± 4.8 vs 16.2 ± 4.1 mg/dL; p < 0.05), insulin (-0.5 ± 2.8 vs 1.7 ± 2.1 UI/L; p < 0.05), HOMA-IR (-0.2 ± 2.1 vs 0.5 ± 2.0 units; p < 0.05), and CRP (-0.3 ± 0.4 vs 1.3 ± 0.2 mg/dL; p < 0.05). Participants with the minor allele assigned to diet S also showed decreases in total cholesterol (-6.1 ± 4.1 vs 14.4 ± 3.1 mg/dL; p < 0.05), LDL-cholesterol (-3.1 ± 2.8 vs 15.0 ± 3.1 mg/dL; p < 0.05), triglycerides (-6.9 ± 4.1 vs 13.2 ± 4.0 mg/dL; p < 0.05), insulin (-0.3 ± 2.1 vs. -1.2 ± 0.2 UI/L: p < 0.05), HOMA-IR (-0.3 ± 2.1 vs. -1.6 ± 1.1 units: p < 0.05), and CRP (-0.4 ± 0.1 vs 1.1 ± 0.2 mg/dL; p < 0.05).

CONCLUSION

In obese Caucasians, the presence of the A allele of the rs16147 genetic variant produces a better metabolic response that is secondary to weight loss with two different hypocaloric diets.

Role of neuropeptide Y gene variant (rs161477) in liver histology in obese patients with non-alcoholic fatty liver disease

BACKGROUND AND RATIONALE

This study was intended to assess the influence of the rs16147 variant of the NPY gene on liver histology in patients with non-alcoholic fatty liver disease (NAFLD).

MATERIAL AND METHODS

Eighty-nine patients with NAFLD were recruited into the study. Serum chemistry tests were done including lipid profile, transaminases, adipokines, and insulin resistance. Genotype of polymorphism (rs161477) of the NPY gene was studied.

RESULTS

Twenty-three patients (25.0%) had the GG genotype (wild type) and sixty-six patients (75%) the GA (n=39) or AA (n=27) (mutant) types. Patients with A allele had a lower percentage of lobular inflammation and steatohepatitis (lobular inflammation plus ballooning) than those with wild genotype. Patients with A allele showed lower SAF (Steatosis, Activity, Fibrosis) scores than non-A allele carriers (5.4±2.7 points vs. 4.1±1.1 points; p=0.01). In the analysis without fibrosis (NAS score), the same differences were detected (4.5±1.8 points vs. 3.4±1.8 points; p=0.01). In the logistic regression analysis A allele carriers showed lower odds for inflammation (OR 0.11, 95% CI 0.02-0.84, p=0.03) and steatohepatitis (OR 0.39, 95% CI 0.14-0.86, p=0.04) after adjusting for age, sex, and body mass index.

CONCLUSIONS

A variant of polymorphism rs16147 of the NPY gene is independently associated to a lower percentage of steatohepatitis and lobular inflammation in obese subjects with biopsy-proven NAFLD.

A Novel Bio-Psychosocial-Behavioral Treatment Model of Panic Disorder

To conceptualize a novel bio-psychosocial-behavioral treatment model of panic disorder (PD), it is necessary to completely integrate behavioral, psychophysiological, neurobiological, and genetic data. Molecular genetic research on PD is specifically focused on neurotransmitters, including serotonin, neuropeptides, glucocorticoids, and neurotrophins. Although pharmacological interventions for PD are currently available, the need for more effective, faster-acting, and more tolerable pharmacological interventions is unmet. Thus, glutamatergic receptor modulators, orexin receptor antagonists, corticotrophin-releasing factor 1 receptor antagonists, and other novel mechanism-based anti-panic therapeutics have been proposed. Research on the neural correlates of PD is focused on the dysfunctional "cross-talk" between emotional drive (limbic structure) and cognitive inhibition (prefrontal cortex) and the fear circuit, which includes the amygdala-hippocampus-prefrontal axis. The neural perspective regarding PD supports the idea that cognitive-behavioral therapy normalizes alterations in top-down cognitive processing, including increased threat expectancy and attention to threat. Consistent with the concept of "personalized medicine," it is speculated that Research Domain Criteria can enlighten further treatments targeting dysfunctions underlying PD more precisely and provide us with better definitions of moderators used to identify subgroups according to different responses to treatment. Structuring of the "negative valence systems" domain, which includes fear/anxiety, is required to define PD. Therefore, targeting glutamate- and orexin-related molecular mechanisms associated with the fear circuit, which includes the amygdala-hippocampus-prefrontal cortex axis, is required to define a novel bio-psychosocial-behavioral treatment model of PD.

A functional genetic variation of SLC6A2 repressor hsa-miR-579-3p upregulates sympathetic noradrenergic processes of fear and anxiety

Increased sympathetic noradrenergic signaling is crucially involved in fear and anxiety as defensive states. MicroRNAs regulate dynamic gene expression during synaptic plasticity and genetic variation of microRNAs modulating noradrenaline transporter gene (SLC6A2) expression may thus lead to altered central and peripheral processing of fear and anxiety. In silico prediction of microRNA regulation of SLC6A2 was confirmed by luciferase reporter assays and identified hsa-miR-579-3p as a regulating microRNA. The minor (T)-allele of rs2910931 (MAF_cases = 0.431, MAF_controls = 0.368) upstream of MIR579 was associated with panic disorder in patients (p_allelic = 0.004, n_cases = 506, n_controls = 506) and with higher trait anxiety in healthy individuals (p_ASI = 0.029, p_ACQ = 0.047, n = 3112). Compared to the major (A)-allele, increased promoter activity was observed in luciferase reporter assays in vitro suggesting more effective MIR579 expression and SLC6A2 repression in vivo (p = 0.041). Healthy individuals carrying at least one (T)-allele showed a brain activation pattern suggesting increased defensive responding and sympathetic noradrenergic activation in midbrain and limbic areas during the extinction of conditioned fear. Panic disorder patients carrying two (T)-alleles showed elevated heart rates in an anxiety-provoking behavioral avoidance test (F(2, 270) = 5.47, p = 0.005). Fine-tuning of noradrenaline homeostasis by a MIR579 genetic variation modulated central and peripheral sympathetic noradrenergic activation during fear processing and anxiety. This study opens new perspectives on the role of microRNAs in the etiopathogenesis of anxiety disorders, particularly their cardiovascular symptoms and comorbidities.

Panic disorders: The role of genetics and epigenetics

Panic disorder is characterized by symptoms with abrupt surges of fear with palpitations, sweating, trembling, heat sensations. Considering its disease burden on each individual and on society, understanding its etiology is important. Though no one specific etiology has been known, like other psychiatric disorders, multiple factors such as genetic, environmental, neurobiological, psychopathological factors have been suggested. In this article, we reviewed currently known etiologies and related study results, regarding especially genetic and epigenetic aspects of the panic disorder. Early studies, including twin studies, family studies, adoption studies suggested highly familial trait of panic disorder. Linkage studies, either, found panic disorder is not a single gene disorder but confirmed existence of multiple related genes. Chromosome and candidate gene studies found few related genes, NPY, ADORA2A, COMT, IKBKE. Newer method, genome-wide association studies (GWAS) have been searching for newer genes. No genome-wide significant genes, however, were detected, confirming previously known candidate genes, NPY5R on 4q31.3-32, BDKRB2 on 14q32, instead. Epigenetic modification has also been studied on many different psychiatric disorders. Monoamine oxidase A (MAOA) hypomethylation, taken together with negative life events, showed relation with panic disorder. Glutamate decarbodylases 1 (GAD1) hypomethylation was also specific on panic disorder patients. Relation with noradrenaline transporter (NET) gene SLC6a2 promoter methylation has also been studied. In conclusion, no specific gene or epigenetic pattern can fully explain etiology of panic disorder. Few genes and epigenetic patterns, however, showed strong association with panic disorder compared to healthy controls. Considering its multivariable background, further studies with larger populations can confirm current results and clarify etiologies of panic disorder.

Neuropeptide Y in Alcohol Addiction and Affective Disorders

Neuropeptide Y (NPY), a neuropeptide highly conserved throughout evolution, is present at high levels in the central nervous system (CNS), as well as in peripheral tissues such as the gut and cardiovascular system. The peptide exerts its effects via multiple receptor subtypes, all belonging to the G-protein-coupled receptor superfamily. Of these subtypes, the Y1 and the Y2 are the most thoroughly characterized, followed by the Y5 subtype. NPY and its receptors have been shown to be of importance in central regulation of events underlying, for example, affective disorders, drug/alcohol use disorders, and energy homeostasis. Furthermore, within the CNS, NPY also affects sleep regulation and circadian rhythm, memory function, tissue growth, and plasticity. The potential roles of NPY in the etiology and pathophysiology of mood and anxiety disorders, as well as alcohol use disorders, have been extensively studied. This focus was prompted by early indications for an involvement of NPY in acute responses to stress, and, later, also data pointing to a role in alterations within the CNS during chronic, or repeated, exposure to adverse events. These functions of NPY, in addition to the peptide's regulation of disease states, suggest that modulation of the activity of the NPY system via receptor agonists/antagonists may be a putative treatment mechanism in affective disorders as well as alcohol use disorders. In this review, we present an overview of findings with regard to the NPY system in relation to anxiety and stress, acute as well as chronic; furthermore we discuss post-traumatic stress disorder and, in part depression. In addition, we summarize findings on alcohol use disorders and related behaviors. Finally, we briefly touch upon genetic as well as epigenetic mechanisms that may be of importance for NPY function and regulation. In conclusion, we suggest that modulation of NPY-ergic activity within the CNS, via ligands aimed at different receptor subtypes, may be attractive targets for treatment development for affective disorders, as well as for alcohol use disorders.

Association of Neuropeptide Y Gene rs16147 Polymorphism with Cardiovascular Risk Factors, Adipokines, and Metabolic Syndrome in Patients with Obesity

BACKGROUND AND AIMS

The NPY gene has 4 exons, and it is located at 7p15.1. The main genetic variant described in this gene is rs16147. The aim of this study was to investigate the relationship of NPY rs16147 with body weight, insulin resistance, serum adipokine levels, and risk of metabolic syndrome (MetS).

METHODS

A population of 1,005 obese patients was analyzed in a cross-sectional survey. Weight, fat mass, waist circumference, blood pressure, basal glucose, C-reactive protein, insulin, insulin resistance (homeostasis model assessment of insulin resistance [HOMA-IR]), lipid profile, and adipocytokine (leptin, adiponectin, and resistin) levels were measured. The genotype of the NPY gene polymorphism (rs16147) was studied.

RESULTS

Body mass index (1.0 ± 0.1; p < 0.05), weight (2.8 ± 0.4 kg; p < 0.05), fat mass (1.8 ± 0.3 kg; p < 0.05), waist circumference (1.9 ± 0.2 cm; p < 0.05), leptin level (15.4 ± 8.2 ng/mL; p < 0.05), insulin level (5.1 ± 1.3 mIU/L; p < 0.05), and HOMA-IR (1.4 ± 0.1 units; p < 0.05) were lower in A allele carriers than in non-A allele carriers in males. Males with an A allele had a lower percentage of MetS (54.8 vs. 69.1%; p < 0.05), central obesity (94.5 vs. 100%; p < 0.05), and hyperglycemia (24.7 vs. 33.8%; p < 0.05) than non-A allele carriers. Logistic regression analysis indicated that male non-A allele carriers had an increased risk of MetS (odds ratio [OR] = 1.26, 95% confidence interval [CI] = 1.17-1.83; p = 0.034), an increased risk of central obesity (OR = 1.08, 95% CI = 1.02-1.11; p = 0.044), and an increased risk of hyperglycemia (OR = 1.20, 95% CI = 1.09-1.79; p = 0.028) after adjusting for age.

CONCLUSIONS

In obese males, the rs164147 polymorphism of the NPY gene is associated with leptin, insulin level, HOMA-IR, and an increased risk of MetS and its related phenotypes, such as central obesity and hyperglycemia.

Candidate genes in panic disorder: meta-analyses of 23 common variants in major anxiogenic pathways

The utilization of molecular genetics approaches in examination of panic disorder (PD) has implicated several variants as potential susceptibility factors for panicogenesis. However, the identification of robust PD susceptibility genes has been complicated by phenotypic diversity, underpowered association studies and ancestry-specific effects. In the present study, we performed a succinct review of case-control association studies published prior to April 2015. Meta-analyses were performed for candidate gene variants examined in at least three studies using the Cochrane Mantel-Haenszel fixed-effect model. Secondary analyses were also performed to assess the influences of sex, agoraphobia co-morbidity and ancestry-specific effects on panicogenesis. Meta-analyses were performed on 23 variants in 20 PD candidate genes. Significant associations after correction for multiple testing were observed for three variants, TMEM132D rs7370927 (T allele: odds ratio (OR)=1.27, 95% confidence interval (CI): 1.15-1.40, P=2.49 × 10(-6)), rs11060369 (CC genotype: OR=0.65, 95% CI: 0.53-0.79, P=1.81 × 10(-5)) and COMT rs4680 (Val (G) allele: OR=1.27, 95% CI: 1.14-1.42, P=2.49 × 10(-5)) in studies with samples of European ancestry. Nominal associations that did not survive correction for multiple testing were observed for NPSR1 rs324891 (T allele: OR=1.22, 95% CI: 1.07-1.38, P=0.002), TPH1 rs1800532 (AA genotype: OR=1.46, 95% CI: 1.14-1.89, P=0.003) and HTR2A rs6313 (T allele: OR=1.19, 95% CI: 1.07-1.33, P=0.002) in studies with samples of European ancestry and for MAOA-uVNTR in female PD (low-active alleles: OR=1.21, 95% CI: 1.07-1.38, P=0.004). No significant associations were observed in the secondary analyses considering sex, agoraphobia co-morbidity and studies with samples of Asian ancestry. Although these findings highlight a few associations, PD likely involves genetic variation in a multitude of biological pathways that is diverse among populations. Future studies must incorporate larger sample sizes and genome-wide approaches to further quantify the observed genetic variation among populations and subphenotypes of PD.

Neuropeptide Y: A stressful review

Stress is defined as an adverse condition that disturbs the homeostasis of the body and activates adaptation responses. Among the many pathways and mediators involved, neuropeptide Y (NPY) stands out due to its unique stress-relieving, anxiolytic and neuroprotective properties. Stress exposure alters the biosynthesis of NPY in distinct brain regions, the magnitude and direction of this effect varying with the duration and type of stress. NPY is expressed in particular neurons of the brainstem, hypothalamus and limbic system, which explains why NPY has an impact on stress-related changes in emotional-affective behaviour and feeding as well as on stress coping. The biological actions of NPY in mammals are mediated by the Y1, Y2, Y4 and Y5 receptors, Y1 receptor stimulation being anxiolytic whereas Y2 receptor activation is anxiogenic. Emerging evidence attributes NPY a role in stress resilience, the ability to cope with stress. Thus there is a negative correlation between stress-induced behavioural disruption and cerebral NPY expression in animal models of post-traumatic stress disorder. Exogenous NPY prevents the negative consequences of stress, and polymorphisms of the NPY gene are predictive of impaired stress processing and increased risk of neuropsychiatric diseases. Stress is also a factor contributing to, and resulting from, neurodegenerative diseases such as Alzheimer's, Parkinson's and Huntington's disease, in which NPY appears to play an important neuroprotective role. This review summarizes the evidence for an implication of NPY in stress-related and neurodegenerative pathologies and addresses the cerebral NPY system as a therapeutic target.

NPY-Y1 coexpressed with NPY-Y5 receptors modulate anxiety but not mild social stress response in mice

The Y1 and Y5 receptors for neuropeptide Y have overlapping functions in regulating anxiety. We previously demonstrated that conditional removal of the Y1 receptor in the Y5 receptor expressing neurons in juvenile Npy1r(Y5R-/-) mice leads to higher anxiety but no changes in hypothalamus-pituitary-adrenocortical axis activity, under basal conditions or after acute restraint stress. In the present study, we used the same conditional system to analyze the specific contribution of limbic neurons coexpressing Y1 and Y5 receptors on the emotional and neuroendocrine responses to social chronic stress, using different housing conditions (isolation vs. group-housing) as a model. We demonstrated that control Npy1r(2lox) male mice housed in groups show increased anxiety and hypothalamus-pituitary-adrenocortical axis activity compared with Npy1r(2lox) mice isolated for six weeks immediately after weaning. Conversely, Npy1r(Y5R-/-) conditional mutants display an anxious-like behavior but no changes in hypothalamus-pituitary-adrenocortical axis activity as compared with their control littermates, independently of housing conditions. These results suggest that group housing constitutes a mild social stress for our B6129S mouse strain and they confirm that the conditional inactivation of Y1 receptors specifically in Y5 receptor containing neurons increases stress-related anxiety without affecting endocrine stress responses.

From neural to genetic substrates of panic disorder: Insights from human and mouse studies

Fear is an ancestral emotion, an intrinsic defensive response present in every organism. Although fear is an evolutionarily advantageous emotion, under certain pathologies such as panic disorder it might become exaggerated and non-adaptive. Clinical and preclinical work pinpoints that changes in cognitive processes, such as perception and interpretation of environmental stimuli that rely on brain regions responsible for high-level function, are essential for the development of fear-related disorders. This review focuses on the involvement of cognitive function to fear circuitry disorders. Moreover, we address how animal models are contributing to understand the involvement of human candidate genes to pathological fear and helping achieve progress in this field. Multidisciplinary approaches that integrate human genetic findings with state of the art genetic mouse models will allow to elucidate the mechanisms underlying pathology and to develop new strategies for therapeutic targeting.

Targeting the Neuropeptide Y System in Stress-related Psychiatric Disorders

Repeated, extreme, or traumatic stressors can elicit pathological effects leading to many negative physical and psychological outcomes. Stressors can precipitate the onset of psychiatric diseases, or exacerbate pre-existing disorders including various anxiety and mood disorders. As stressors can negatively impact human psychiatric health, it is essential to identify neurochemicals that may confer protection from the negative sequelae of repeated or extreme stress exposure. Elucidating the neurobiological underpinnings of stress resilience will enhance our ability to promote resilience to, or recovery from, stress-related psychiatric disease. Herein, we will review the evidence for neuropeptide Y as an endogenous mediator of resilience and its potential relevance for the treatment of stress-related psychiatric diseases.

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Overview of neuropeptide Y and receptor subtypes in the central nervous system.

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Alterations of neuropeptide Y in human stress-related psychiatric disorders.

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Evidence for neuropeptide Y in resilience to stress-related emotionality in rodent behavioral models.

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Pharmacotherapeutic implications for neuropeptide Y in the treatment of stress-related psychiatric disorders.

Conditional inactivation of neuropeptide Y Y1 receptors unravels the role of Y1 and Y5 receptors coexpressing neurons in anxiety

BACKGROUND

The Y1 receptor (Y1R) and Y5 receptor (Y5R) for neuropeptide Y share similar actions in the regulation of anxiety. Previously demonstrated that conditional removal of the Y1R during postnatal development in the forebrain excitatory neurons leads to higher anxiety, increased hypothalamus-pituitary-adrenocortical axis activity, and decreased body growth rate in male mice raised by foster mothers that exhibit high levels of maternal care. In the present study, we used the same conditional system to analyze the specific contribution to emotional behavior and stress response of the Y1R coexpressed with the Y5R.

METHODS

Using the Cre-loxP recombination system, we investigated anxious behavior, spatial memory, and metabolic functions of conditional knockout mice in which the inactivation of the Npy1r gene was induced in the Y5Rs expressing neurons of juvenile mice (Npy1r(Y5R-/-) ).

RESULTS

Npy1r(Y5R-/-) mice show increased anxiety-related behavior but no changes in hypothalamus-pituitary-adrenocortical axis activity or in body weight growth, independently of gender and mouse strain used as foster mothers. Also, Npy1r(Y5R-/-) mice of both genders display increased spatial reference memory in the Morris water maze test.

CONCLUSIONS

The results suggest that neuropeptide Y Y1R differentially expressed in the limbic system regulates anxiety and stress responses via distinct neurochemical circuits. In addition, we provide the first experimental genetic evidence that the Y1Rs coexpressed with the Y5R are involved in retention of spatial memory in male and female mice.

Lack of an association between a functional polymorphism in the neuropeptide Y gene promoter and the presence of coronary artery disease in an Iranian population

BACKGROUND/AIMS

Several genetic factors have been identified that may contribute to the risk of coronary artery disease (CAD). Variants of the neuropeptide Y (NPY) gene, whose products play an important role in regulating several physiological functions, have been associated with the risk of CAD in some populations. The purpose of this study was to investigate the relationship between the NPY gene rs16147 polymorphism and the presence of CAD in an Iranian population.

METHODS

DNA samples of 922 subjects, including 433 with angiographically defined CAD (CAD+), 196 without angiographically defined significant CAD (CAD-) and 293 controls, were genotyped using polymerase chain reaction based on the amplification-refractory mutation system. Logistic regression analyses were performed to assess the association of rs16147 genotypes with the presence of significant CAD.

RESULTS

Although logistic regression analysis indicated that the NPY polymorphism rs16147 was nominally associated with an increased risk of CAD (p < 0.05), after adjustment for confounding factors, there was no evidence for any significantly increased or decreased risk of CAD with this polymorphism. However, in stratified analyses, the C allele was significantly associated with a reduced risk of CAD in males and subjects who were <50 years of age.

CONCLUSIONS

This study suggests that the rs16147 polymorphism in the NPY gene may not be a potential contributor to the risk of CAD in an Iranian population.

The diagnosis of and treatment recommendations for anxiety disorders

BACKGROUND

Anxiety disorders (panic disorder/agoraphobia, generalized anxiety disorder, social phobia, and specific phobias) are the most common mental illnesses. For example, the 12-month prevalence of panic disorder/agoraphobia is 6%.

METHOD

This guideline is based on controlled trials of psychotherapy and pharmacotherapy, retrieved by a systematic search for original articles that were published up to 1 July 2013. Experts from 20 specialty societies and other organizations evaluated the evidence for each treatment option from all available randomized clinical trials and from a synthesis of the recommendations of already existing international and German guidelines.

RESULTS

403 randomized controlled trials were evaluated. It was concluded that anxiety disorders should be treated with psychotherapy, psychopharmacological drugs, or both. Response rates to initial treatment vary from 45% to 65%. Cognitive behavioral therapy is supported by higher-level evidence than any other psychotherapeutic technique. Psychodynamic therapy is recommended as a second-line treatment. Among anxiolytic drugs, the agents of first choice are selective serotonin reuptake inhibitors and serotoninnorepinephrine reuptake inhibitors. The patient's preference should be considered in the choice of treatment. Drug treatment should be continued for 6 to 12 months after remission. If psychotherapy or drug treatment is not adequately effective, then the treatment should be switched to the other form, or to a combination of both.

CONCLUSION

The large amount of data now available from randomized controlled trials permits the formulation of robust evidence-based recommendations for the treatment of anxiety disorders. Future work should more closely address the necessary duration of psychotherapy and the efficacy of combined psychotherapy and drug treatment.

Epigenetic signature of panic disorder: a role of glutamate decarboxylase 1 (GAD1) DNA hypomethylation?

Glutamate decarboxylases (GAD67/65; GAD1/GAD2) are crucially involved in gamma-aminobutyric acid (GABA) synthesis and thus were repeatedly suggested to play an important role in the pathogenesis of anxiety disorders. In the present study, DNA methylation patterns in the GAD1 and GAD2 promoter and GAD1 intron 2 regions were investigated for association with panic disorder, with particular attention to possible effects of environmental factors. Sixty-five patients with panic disorder (f=44, m=21) and 65 matched healthy controls were analyzed for DNA methylation status at 38 GAD1 promoter/intron2 and 10 GAD2 promoter CpG sites via direct sequencing of sodium bisulfate treated DNA extracted from blood cells. Recent positive and negative life events were ascertained. Patients and controls were genotyped for GAD1 rs3762556, rs3791878 and rs3762555, all of which are located in the analyzed promoter region. Patients with panic disorder exhibited significantly lower average GAD1 methylation than healthy controls (p<0.001), particularly at three CpG sites in the promoter as well as in intron 2. The occurrence of negative life events was correlated with relatively decreased average methylation mainly in the female subsample (p=0.01). GAD1 SNP rs3762555 conferred a significantly lower methylation at three GAD1 intron 2 CpG sites (p<0.001). No differential methylation was observed in the GAD2 gene. The present pilot data suggest a potentially compensatory role of GAD1 gene hypomethylation in panic disorder possibly mediating the influence of negative life events and depending on genetic variation. Future studies are warranted to replicate the present finding in independent samples, preferably in a longitudinal design.

Effects of ADORA2A gene variation and caffeine on prepulse inhibition: a multi-level risk model of anxiety

The complex pathogenesis of anxiety and panic disorder in particular has been suggested to be influenced by genetic factors such as the adenosine A2A receptor gene (ADORA2A) 1976T>C polymorphism (rs5751876) as well as neuropsychological factors such as early information processing deficits. In 114 healthy individuals (males=57, females=57) controlled for anxiety sensitivity (AS), a multi-level risk model of the development of anxiety was applied: Genetic (ADORA2A 1976T>C variant) and biochemical (300 mg of caffeine citrate vs. placebo) factors were hypothesized to influence early information processing as measured by the prepulse inhibition/facilitation paradigm (stimulus onset asynchronies (SOAs) of 60, 120, 240, 480 and 2000ms between prepulses and startle stimuli). A fourfold interaction of genotype, intervention, gender, and SOAs was discerned. Stratification by SOAs revealed that at 120 ms and 240 ms SOAs in the caffeine condition, PPI was impaired in female ADORA2A 1976TT risk genotype carriers as compared to male ADORA2A 1976TT homozygotes, while no significant effects were observed in the ADORA2A 1976CC/CT non-risk genotype or placebo group. Only in high anxiety sensitive probands, a significant intervention effect was discerned with impaired prepulse facilitation (PPF) due to caffeine. The present results point to an impaired ability to selectively process very early information and to gate irrelevant sensory information, respectively, in female ADORA2A 1976TT homozygotes in response to caffeine, providing further evidence for the adenosinergic system to be involved in the pathogenesis of anxiety.

Lateral septal infusions of the neuropeptide Y Y2 receptor agonist, NPY(13-36) differentially affect different defensive behaviors in male, Long Evans rats

The lateral septum has been extensively implicated in regulating anxiety-related defensive behaviors in the rat. Neuropeptide Y (NPY) contributes to anxiety, likely through activity at the NPY Y1 and/or Y2 receptor binding sites. Although the lateral septum contains the highest density of Y2 receptors in brain, the involvement of this receptor in anxiety-related defensive behaviors is not clear. Thus, the purpose of the current study was to characterize lateral septal Y2 receptor contributions to rats' defensive responses to threat and/or potentially threatening environments. We investigated this by infusing the NPY Y2 agonist NPY13-36 into the lateral septum and testing rats across a battery of animal models of anxiety (Experiment 1). To verify the role of Y2 in mediating the observed effects, rats were pre-infused with the potent and highly selective Y2 antagonist BIIE 0246 prior to infusion with NPY13-36 (Experiment 2). Infusions of NPY13-36 into the lateral septum increased rats' open-arm exploration in the elevated plus-maze test (p<0.01) and decreased the proportion of rats' that buried (p<0.05) as well as their latency to initiate burying in the shock-probe burying test (p<0.01). By contrast, NPY13-36 did not affect either anxiety- or appetite-related responses in the novelty-induced suppression of feeding test (all ps>0.3; Experiment 1). Pre-treatment with the Y2 antagonist BIIE 0246 prevented the anxiolytic-like actions of NPY13-36 in the plus-maze but not in the shock-probe test (Experiment 2). Thus, it appears that the anxiolytic-like actions of lateral septal NPY13-36 are mediated by the Y2 receptor in a test-specific manner.

Meta-analysis of genome-wide association studies for panic disorder in the Japanese population

Panic disorder (PD) is a moderately heritable anxiety disorder whose pathogenesis is not well understood. Due to the lack of power in previous association studies, genes that are truly associated with PD might not be detected. In this study, we conducted a genome-wide association study (GWAS) in two independent data sets using the Affymetrix Mapping 500K Array or Genome-Wide Human SNP Array 6.0. We obtained imputed genotypes for each GWAS and performed a meta-analysis of two GWAS data sets (718 cases and 1717 controls). For follow-up, 12 single-nucleotide polymorphisms (SNPs) were tested in 329 cases and 861 controls. Gene ontology enrichment and candidate gene analyses were conducted using the GWAS or meta-analysis results. We also applied the polygenic score analysis to our two GWAS samples to test the hypothesis of polygenic components contributing to PD. Although genome-wide significant SNPs were not detected in either of the GWAS nor the meta-analysis, suggestive associations were observed in several loci such as BDKRB2 (P=1.3 × 10(-5), odds ratio=1.31). Among previous candidate genes, supportive evidence for association of NPY5R with PD was obtained (gene-wise corrected P=6.4 × 10(-4)). Polygenic scores calculated from weakly associated SNPs (P<0.3 and 0.4) in the discovery sample were significantly associated with PD status in the target sample in both directions (sample I to sample II and vice versa) (P<0.05). Our findings suggest that large sets of common variants of small effects collectively account for risk of PD.

The selective neuropeptide Y Y5 agonist [cPP(1-7),NPY(19-23),Ala31,Aib32,Gln34]hPP differently modulates emotional processes and body weight in the rat

The neuropeptide Y (NPY) has been suggested to act as a major regulator of emotional processes and body weight. The full spectrum of biological effects of this peptide is mediated by at least four classes of receptors known as the Y(1), Y(2), Y(4), and Y(5) subtypes. However, the respective contribution of each of these receptor subtypes, especially the Y(5) subtype, in emotional processes is still mostly unknown. In the present study, we investigated the effect of long term administration of a selective Y(5) agonist [cPP(1-7),NPY(19-23),Ala(31),Aib(32),Gln(34)]hPP on emotional processes and body weight using two rat models of emotional dysfunctions, the corticosterone (CORT)-induced anxiety model as well as the olfactory bulbectomized (OBX) model of depression and anxiety in Wistar and Sprague-Dawley rats, respectively. The sub-chronic administration of the Y(5) agonist reversed the high levels of locomotion, rearing and grooming in the open field test and the impaired social activity induced by OBX, while increased the percentage of entries and time in the open arm of the elevated plus maze in CORT-treated rats. Furthermore, this Y(5) agonist increased body weight in both strains of control rats. These data further demonstrate that Y(5) receptors are not only involved in the control of body weight but also mediate emotional processing under challenged conditions. Thus, the pharmacotherapeutic administration of a Y(5) agonist could be considered as a potentially novel strategy to alleviate some forms of anxiety and depression in humans.

Central functions of neuropeptide Y in mood and anxiety disorders

INTRODUCTION

Neuropeptide Y (NPY) is a highly conserved neuropeptide belonging to the pancreatic polypeptide family. Its potential role in the etiology and pathophysiology of mood and anxiety disorders has been extensively studied. NPY also has effects on feeding behavior, ethanol intake, sleep regulation, tissue growth and remodeling. Findings from animal studies have delineated the physiological and behavioral effects mediated by specific NPY receptor subtypes, of which Y1 and Y2 are the best understood.

AREAS COVERED

Physiological roles and alterations of the NPYergic system in anxiety disorders, depression, posttraumatic stress disorder (PTSD), alcohol dependence and epilepsy. For each disorder, studies in animal models and human investigations are outlined and discussed, focusing on behavior, neurophysiology, genetics and potential for novel treatment targets.

EXPERT OPINION

The wide implications of NPY in psychiatric disorders such as depression and PTSD make the NPYergic system a promising target for the development of novel therapeutic interventions. These include intranasal NPY administration, currently under study, and the development of agonists and antagonists targeting NPY receptors. Therefore, we are proposing that via this mode of administration, NPY might exert CNS therapeutic actions without untoward systemic effects. Future work will show if this is a feasible approach.

ADORA2A Gene variation, caffeine, and emotional processing: a multi-level interaction on startle reflex

There is converging evidence for genetic, biochemical, and neuropsychological factors to increase the risk for anxiety and anxiety disorders. The pathogenesis of anxiety disorders is assumed to be influenced by a complex interaction of these individual risk factors on several levels, affecting intermediate phenotypes of anxiety such as the startle reflex. Thus, in the present double-blind, placebo-controlled study we attempted to paradigmatically investigate a multi-level pathogenetic model of anxiety by testing the effect of 300 mg caffeine citrate as an antagonist at the adenosine A2A receptor vs placebo on the emotion-potentiated (unpleasant, neutral, and pleasant International Affective Picture System pictures) startle reflex in 110 healthy individuals (male=56, female=54) stratified for the adenosine A2A receptor (ADORA2A) 1976T>C polymorphism (rs5751876). In addition to the expected main effect of picture category (highest startle amplitude for unpleasant, lowest for pleasant pictures) groups across all ADORA2A 1976T>C genotype and intervention (caffeine vs placebo) groups, an interaction effect of genotype, intervention, and picture category was discerned: In ADORA2A 1976TT risk genotype carriers, highest startle magnitudes were observed after caffeine administration in response to unpleasant pictures, with this effect arising particularly from the female subgroup. Our data point to a complex, multi-level, and potentially gender-specific pathogenetic model of anxiety, with genetic and biochemical factors interactively increasing the risk of maladaptive emotional processing and thereby possibly also anxiety disorders. The present findings may eventually aid in improving primary and secondary prevention by sharpening the risk profiles of anxiety-prone individuals.

Behavioral genetics of affective and anxiety disorders

As shown by clinical genetic studies, affective and anxiety disorders are complex genetic disorders with genetic and environmental factors interactively determining their respective pathomechanism. Advances in molecular genetic techniques including linkage studies, association studies, and genome-wide association studies allow for the detailed dissection of the genetic influence on the development of these disorders. Besides the molecular genetic investigation of categorical entities according to standardized diagnostic criteria, intermediate phenotypes comprising neurobiological or neuropsychological traits (e.g., neuronal correlates of emotional processing) that are linked to the disease of interest and that are heritable, have been proposed to be closer to the underlying genotype than the overall disease phenotype. These intermediate phenotypes are dimensional and more precisely defined than the categorical disease phenotype, and therefore have attracted much interest in the genetic investigation of affective and anxiety disorders. Given the complex genetic nature of affective and anxiety disorders with an interaction of multiple risk genes and environmental influences, the interplay of genetic factors with environmental factors is investigated by means of gene-environment interaction (GxE) studies. Pharmacogenetic studies aid in the dissection of the genetically influenced heterogeneity of psychotropic drug response and may contribute to the development of a more individualized treatment of affective and anxiety disorders. Finally, there is some evidence for genetic factors potentially shared between affective and anxiety disorders pointing to a possible overlapping phenotype between anxiety disorders and depression.

Neuropeptide S receptor gene -- converging evidence for a role in panic disorder

Animal studies have suggested neuropeptide S (NPS) and its receptor (NPSR) to be involved in the pathogenesis of anxiety-related behavior. In this study, a multilevel approach was applied to further elucidate the role of NPS in the etiology of human anxiety. The functional NPSR A/T (Asn¹⁰⁷Ile) variant (rs324981) was investigated for association with (1) panic disorder with and without agoraphobia in two large, independent case-control studies, (2) dimensional anxiety traits, (3) autonomic arousal level during a behavioral avoidance test and (4) brain activation correlates of anxiety-related emotional processing in panic disorder. The more active NPSR rs324981 T allele was found to be associated with panic disorder in the female subgroup of patients in both samples as well as in a meta-analytic approach. The T risk allele was further related to elevated anxiety sensitivity, increased heart rate and higher symptom reports during a behavioral avoidance test as well as decreased activity in the dorsolateral prefrontal, lateral orbitofrontal and anterior cingulate cortex during processing of fearful faces in patients with panic disorder. The present results provide converging evidence for a female-dominant role of NPSR gene variation in panic disorder potentially through heightened autonomic arousal and distorted processing of anxiety-relevant emotional stimuli.

Genetics of panic disorder: focus on association studies and therapeutic perspectives

There is evidence for either genetic heterogeneity or complex inheritance with an interaction of environmental factors and multiple single genes in the etiology of panic disorder. Although linkage analyses of panic disorder have implicated several chromosomal regions including 1q, 2q, 4q, 7p, 9q, 12q, 13q, 15q and 22q, they so far have not been able to identify a major gene responsible for panic disorder. Several genes of classical candidate neurotransmitter systems have been reported to be associated with panic disorder. Genetic variation in genes of monoamine oxidase A, catechol-O-methyltransferase, adenosine receptor (ADORA2A) and cholecystokinin B receptor have been inconsistently replicated. There are multiple lines of evidence for highly relevant effects of gender and ethnicity. Future research strategies might focus on broad phenotypes defined by comorbidity or intermediate phenotypes and include the use of animal models for identifying candidate genes, such as the regulator of G-protein signaling (RGS2) gene, genome-wide association studies in large samples, studies of gene-gene and gene-environment interactions and pharmacogenetic studies. The identification of novel pathophysiological pathways may provide the basis for the development of novel therapeutic interventions.

Advances in molecular genetics of panic disorder

The molecular genetic research on panic disorder (PD) has grown tremendously in the past decade. Although the data from twin and family studies suggest an involvement of genetic factors in the familial transmission of PD with the heritability estimate near 40%, the genetic substrate underlying panicogenesis is not yet understood. The linkage studies so far have suggested that chromosomal regions 13q, 14q, 22q, 4q31-q34, and probably 9q31 are associated with the transmission of PD phenotypes. To date, more than 350 candidate genes have been examined in association studies of PD, but most of these results remain inconsistent, negative, or not clearly replicated. Only Val158Met polymorphism of the catechol-O-methyltransferase gene has been implicated in susceptibility to PD by several studies in independent samples and confirmed in a recent meta-analysis. However, the specific role of this genetic variation in PD requires additional analysis considering its gender- and ethnicity-dependent effect and putative impact on cognitive functions. The recent advantages in bioinformatics and genotyping technologies, including genome-wide association and gene expression methods, provide the means for far more comprehensive discovery in PD. The progress in clinical and neurobiological concepts of PD may further guide genetic research through the current controversies to more definitive findings.

Neuropeptide Y (NPY) gene: Impact on emotional processing and treatment response in anxious depression

Neuropeptide Y (NPY) has been found to play a role in the pathomechanism of both anxiety and depression. Thus, NPY is a promising candidate in the investigation of the clinical phenotype of "anxious depression". Five NPY gene variants were investigated for an influence on antidepressant treatment response in a sample of 256 patients with depression. Additionally, NPY gene impact on amygdala activation during facial emotion processing was analyzed in a subsample of 35 depressed patients. Particularly in anxious depression, the less active NPY rs16147 -399C allele conferred slow response after 2weeks and failure to achieve remission after four weeks of treatment. The rs16147 C allele was further associated with stronger bilateral amygdala activation in response to threatening faces in an allele-dose fashion. The present results point towards a possible influence of functional NPY gene variation on antidepressant treatment response in anxious depression, potentially conveyed by altered emotional processing.

Mechanism of action in CBT (MAC): methods of a multi-center randomized controlled trial in 369 patients with panic disorder and agoraphobia

Cognitive behavioral therapy (CBT) is efficacious for panic disorder with agoraphobia (PD/A). Nevertheless, the active ingredients of treatment and the mechanisms through which CBT achieves its effects remain largely unknown. The mechanisms of action in CBT (MAC) study was established to investigate these questions in 369 patients diagnosed with PD/A. The MAC study utilized a multi-center, randomized controlled design, with two active treatment conditions in which the administration of exposure was varied, and a wait-list control group. The special feature of MAC is the way in which imbedded experimental, psychophysiological, and neurobiological paradigms were included to elucidate therapeutic and psychopathological processes. This paper describes the aims and goals of the MAC study and the methods utilized to achieve them. All aspects of the research design (e.g., assessments, treatment, experimental procedures) were implemented so as to facilitate the detection of active therapeutic components, and the mediators and moderators of therapeutic change. To this end, clinical, behavioral, physiological, experimental, and genetic data were collected and will be integrated.

Anxiety in mice and men: a comparison

Anxiety is one of the most fundamental emotions required to survive or to cope with potential threatening stimuli. Under certain circumstances, it can change to excessive or maladaptive response and might manifest in anxious personality or even anxiety disorders. Genetic studies provide a number of promising candidate genes that, however, account for only a few percent of the phenotypic variance. Social and material environmental effects such as stressful life events, drugs or chemicals and particular behavioural influences such as parental care are suggested to interact with gene effects presumably involving epigenetic processes. Such interaction probably modifies an individual's predisposition, personality and susceptibility to develop normal or low anxiety or even maladaptive or excessive anxiety. Since human anxiety involves complex emotions as well as cognitions, unique experiences and an individual genetic make-up, studies trying to clarify the complex and functionally interwoven pathogenesis of anxious personality or anxiety disorders often adopt a reductionistic, simplifying approach. Therein, mice constitute an invaluable tool for modelling human anxiety in its various forms as they display remarkable similarities on anatomical, physiological, biochemical, molecular and behavioural levels. This review aims to fit observations and results obtained from men and mice on behavioural, genetic and environmental levels in response to different threatening stimuli elucidating different genetic and epigenetic effects.

The novel neuropeptide Y Y5 receptor antagonist Lu AA33810 [N-[[trans-4-[(4,5-dihydro[1]benzothiepino[5,4-d]thiazol-2-yl)amino]cyclohexyl]methyl]-methanesulfonamide] exerts anxiolytic- and antidepressant-like effects in rat models of stress sensitivity

Neuropeptide Y (NPY) regulates physiological processes via receptor subtypes (Y(1), Y(2), Y(4), Y(5), and y(6)). The Y(5) receptor is well known for its role in appetite. Based on expression in the limbic system, we hypothesized that the Y(5) receptor might also modulate stress sensitivity. We identified a novel Y(5) receptor-selective antagonist, Lu AA33810 [N-[[trans-4-[(4,5-dihydro[1]-benzothiepino[5,4-d]thiazol-2-yl)amino]cyclohexyl]methyl]-methanesulfonamide], that bound to cloned rat Y(5) receptors (K(i) = 1.5 nM) and antagonized NPY-evoked cAMP and calcium mobilization in vitro. Lu AA33810 (3-30 mg/kg p.o.) blocked feeding elicited by intracerebroventricular injection of the Y(5) receptor-selective agonist [cPP(1-7),NPY(19-23),Ala(31),Aib(32),Gln(34)]-hPancreatic Polypeptide in Sprague-Dawley rats. In vivo effects of Lu AA33810 were correlated with brain exposure > or = 50 ng/g and ex vivo Y(5) receptor occupancy of 22 to 95%. Lu AA33810 was subsequently evaluated in models of stress sensitivity. In Fischer 344 rats, Lu AA33810 (30 mg/kg p.o.) attenuated increases in plasma ACTH and corticosterone elicited by intracerebroventricular injection of [cPP(1-7),NPY(19-23),Ala(31),Aib(32),Gln(34)]-hPancreatic Polypeptide. In Sprague-Dawley rats subjected to the social interaction test, Lu AA33810 (3-30 mg/kg p.o.) produced anxiolytic-like effects after acute or chronic treatment. In Flinders sensitive line rats, chronic dosing of Lu AA33810 (10 mg/kg/day i.p.) produced anxiolytic-like effects in the social interaction test, plus antidepressant-like effects in the forced swim test. In Wistar rats exposed to chronic mild stress, chronic dosing of Lu AA33810 (3 and 10 mg/kg/day i.p.) produced antidepressant-like activity, i.e., normalization of stress-induced decrease in sucrose consumption. We propose that Y(5) receptors may function as part of an endogenous stress-sensing system to mediate social anxiety and reward or motivational deficits in selected rodent models.