Experimental Social Stress: Dopaminergic Receptors, Oxidative Stress, and c-Fos Protein Are Involved in Highly Aggressive Behavior

The Role of Parent-Child Attachment, Hostile Attribution Bias in Aggression: A Meta-Analytic Review

Parent-Child Attachment (PCA) and Hostile Attribution Bias (HAB) are closely related to aggression, but findings regarding their relationships are inconsistent. There is a lack of understanding of the underlying mechanism between PCA and aggression. This review employed meta-analysis approaches to investigate the associations between PCA and aggression, as well as between HAB and aggression, and the mechanism for the PCA-aggression association. An article search was conducted in CNKI, PubMed, PsycINFO, Web of Science, ProQuest, and Google Scholar. Totally, 118 studies involving general populations and those at high risk for aggression were included. Results revealed negative associations between Parent-Child Attachment Security (PCAS) and aggression (ρ = -.267, p < .001) and positive associations between Parent-Child Attachment Insecurity (PCAI) and aggression (ρ = .240, p < .05). HAB and aggression were found to be positively associated (ρ = .303, p < .001). As for the PCAS-aggression association, a larger effect size was found in females than in males. The HAB-reactive aggression association was stronger than the HAB-proactive aggression association. In Eastern culture, the association between HAB and aggression was stronger than in Western culture. HAB mediated the association between PCAS and aggression. Our findings contribute to the understanding of the occurrence and development of aggression by establishing an association between attachment theory and the social information processing model. The practical implications include interventions targeting cultivating PCAS and alleviating HAB, which might serve as effective ways to reduce aggression, yet aggression type, gender, and cultural background should be taken into consideration.

Influence of leptin and its receptors on individuals under chronic social stress behavior

Stress is the body's physiological reaction to a dangerous or threatening situation, leading to a state of alertness. This reaction is necessary for developing an effective adaptive response to stress and maintaining the body's homeostasis. Chronic stress, caused mainly by social stress, is what primarily affects the world's population. In the last decades, the emergence of psychological disorders in humans has become more frequent, and one of the symptoms that can be observed is aggressiveness. In the brain, stress can cause neuronal circuit alterations related to the action of hormones in the central nervous system. Leptin, for example, is a hormone capable of acting in brain regions and neuronal circuits important for behavioral and emotional regulation. This study investigated the correlation between chronic social stress, neuroendocrine disorders, and individual behavioral changes. Then, leptin and its receptors' anatomical distribution were evaluated in the brains of mice subjected to a protocol of chronic social stress. The model of spontaneous aggression (MSA) is based on grouping young mice and posterior regrouping of the same animals as adults. According to the regrouping social stress, we categorized the mice into i) harmonic, ii) attacked, and iii) aggressive animals. For leptin hormone evaluation, we quantified plasma and brain concentrations by ELISA and evaluated its receptor and isoform expression by western blotting. Moreover, we verified whether stress or changes in leptin levels interfered with the animal's body weight. Only attacked animals showed reduced plasma leptin concentration and weight gain, besides a higher expression of the high-molecular-weight leptin receptor in the amygdala and the low-molecular-weight receptor in the hippocampal region. Aggressive animals showed a reduction in the cerebral concentration of leptin in the hippocampus and a reduced high-and low-molecular-weight leptin receptor expression in the amygdala. The harmonic animals showed a reduction in the cerebral concentration of leptin in the pituitary and a reduced expression of the high-molecular-weight leptin receptor in the amygdala. We then suggest that leptin and its receptors' expression in plasma and specific brain areas are involved in how individuals react in stressful situations, such as regrouping stress in MSA.

Support from parents, teachers, and peers and the moderation of subjective and objective stress of secondary school student

During adolescence, students increasingly report suffering from stress and school burnout, which poses a risk to students' healthy development. However, social support may counteract perceived stress according to the Buffering Hypothesis and the Conservation of Resources Theory. In search of factors that would support healthy student development, studies have primarily focused on self-report data and neglected biophysiological processes. Addressing this research desideratum, this study examined whether perceived social support buffers the interplay of self-reported stress considering biophysiological markers (i.e., cortisol, alpha-amylase, oxidative stress, and telomere length). 83 secondary school students (Mage = 13.72, SD = 0.67; 48% girls) from Germany participated in a questionnaire study and biophysiological testing. Moderation analyses in R revealed that support from parents moderated the relationships between psychological stress as well as cynicism and inadequacy at school linked to alpha-amylase.

The Association Between Child Abuse and Aggressive Behavior: A Three-Level Meta-Analysis

Child abuse is considered to be an essential factor in the development of aggressive behavior. The intensity of the positive relations between child abuse and aggressive behavior differed considerably among researches despite the fact that abundant studies have observed this relation. According to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) approach, a three-level meta-analysis was employed to obtain reliable estimates for the sizes of effects and investigate some potential moderators of the relation between child abuse and aggressive behavior. The present study obtained 51 studies (30,566 participants; 680 effect sizes) through performing the detailed literature search. It was found that child abuse was positively associated with aggressive behavior in the current study. In addition, the present meta-analysis observed significant moderating effects for type of child abuse, culture, measurement of child abuse, and publication year in the association between child abuse and aggressive behavior. This study suggests that child abuse is a predictor for the development of aggressive behavior in humans. Moreover, child abuse is an important aspect for consideration in efforts toward strengthening of interventions targeting individuals' aggressive behavior.

Minimal influence of estrous cycle on studies of female mouse behaviors

Introduction

Sex bias has been an issue in many biomedical fields, especially in neuroscience. In rodent research, many scientists only focused on male animals due to the belief that female estrous cycle gives rise to unacceptable, high levels of variance in the experiments. However, even though female sexual behaviors are well known to be regulated by estrous cycle, which effects on other non-sexual behaviors were not always consistent in previous reports. Recent reviews analyzing published literature even suggested that there is no evidence for larger variation in female than male in several phenotypes.

Methods

To further investigate the impact of estrous cycle on the variability of female behaviors, we conducted multiple behavioral assays, including the open field test, forced swimming test, and resident-intruder assay to assess anxiety-, depression-like behaviors, as well as social interaction respectively. We compared females in the estrus and diestrus stages across four different mouse strains: C57BL/6, BALB/c, C3H, and DBA/2.

Results

Our results found no significant difference in most behavioral parameters between females in these two stages. On the other hand, the differences in behaviors among certain strains are relatively consistent in both stages, suggesting a very minimal effect of estrous cycle for detecting the behavioral difference. Last, we compared the behavioral variation between male and female and found very similar variations in most behaviors between the two sexes.

Discussion

While our study successfully identified behavioral differences among strains and between the sexes, we did not find solid evidence to support the notion that female behaviors are influenced by the estrous cycle. Additionally, we observed similar levels of behavioral variability between males and females. Female mice, therefore, have no reason to be excluded in future behavioral research.

Chlorpromazine, an Inverse Agonist of D1R-Like, Differentially Targets Voltage-Gated Calcium Channel (CaV) Subtypes in mPFC Neurons

The dopamine receptor type 1 (D1R) and the dopamine receptor type 5 (D5R), which are often grouped as D1R-like due to their sequence and signaling similarities, exhibit high levels of constitutive activity. The molecular basis for this agonist-independent activation has been well characterized through biochemical and mutagenesis in vitro studies. In this regard, it was reported that many antipsychotic drugs act as inverse agonists of D1R-like constitutive activity. On the other hand, D1R is highly expressed in the medial prefrontal cortex (mPFC), a brain area with important functions such as working memory. Here, we studied the impact of D1R-like constitutive activity and chlorpromazine (CPZ), an antipsychotic drug and D1R-like inverse agonist, on various neuronal Ca_V conductances, and we explored its effect on calcium-dependent neuronal functions in the mouse medial mPFC. Using ex vivo brain slices containing the mPFC and transfected HEK293T cells, we found that CPZ reduces Ca_V2.2 currents by occluding D1R-like constitutive activity, in agreement with a mechanism previously reported by our lab, whereas CPZ directly inhibits Ca_V1 currents in a D1R-like activity independent manner. In contrast, CPZ and D1R constitutive activity did not affect Ca_V2.1, Ca_V2.3, or Ca_V3 currents. Finally, we found that CPZ reduces excitatory postsynaptic responses in mPFC neurons. Our results contribute to understanding CPZ molecular targets in neurons and describe a novel physiological consequence of CPZ non-canonical action as a D1R-like inverse agonist in the mouse brain.

Neurobiology of Aggression-Review of Recent Findings and Relationship with Alcohol and Trauma

Aggression can be conceptualized as any behavior, physical or verbal, that involves attacking another person or animal with the intent of causing harm, pain or injury. Because of its high prevalence worldwide, aggression has remained a central clinical and public safety issue. Aggression can be caused by several risk factors, including biological and psychological, such as genetics and mental health disorders, and socioeconomic such as education, employment, financial status, and neighborhood. Research over the past few decades has also proposed a link between alcohol consumption and aggressive behaviors. Alcohol consumption can escalate aggressive behavior in humans, often leading to domestic violence or serious crimes. Converging lines of evidence have also shown that trauma and posttraumatic stress disorder (PTSD) could have a tremendous impact on behavior associated with both alcohol use problems and violence. However, although the link between trauma, alcohol, and aggression is well documented, the underlying neurobiological mechanisms and their impact on behavior have not been properly discussed. This article provides an overview of recent advances in understanding the translational neurobiological basis of aggression and its intricate links to alcoholism and trauma, focusing on behavior. It does so by shedding light from several perspectives, including in vivo imaging, genes, receptors, and neurotransmitters and their influence on human and animal behavior.

Effects of stress on school bullying behavior among secondary school students: Moderating effects of gender and grade level

This study investigated the effects of stress on school bullying behaviors among middle school students, and the moderating role of gender and grade level in this relationship. To this end, the Olweus Child Bullying Questionnaire (OBVQ) secondary school version of the child bullying questionnaire and the stressor scale for secondary school students were used to survey 3,566 secondary school students in Guizhou Province, and the data were statistically analyzed. Results showed that stress was significantly and positively associated with school bullying among secondary school students. Furthermore, both gender and grade moderated the relationship between stress and school bullying, showing that boys and middle school children are more likely to engage in bullying than girls and high school students, respectively. The results of the study provide a theoretical basis for the prevention and intervention of school bullying behaviors among middle school students.

Altered gut microbiota and its metabolites correlate with plasma cytokines in schizophrenia inpatients with aggression

BACKGROUND

The pathophysiological mechanisms of aggression are manifold and they may closely interconnect. Current study aimed to determine the gut microbiota and its metabolites, and clarify their correlations with inflammation, oxidation, leaky gut and clinical profiles underlying aggression in schizophrenia (ScZ).

METHODS

Serum and stool specimens from ScZ inpatients with (ScZ-Ag, 25 cases) and without aggression (NScZ-Ag, 25 cases) were collected. Systemic inflammation, oxidation and leaky gut biomarkers were determined by ELISA, gut microbiota by 16S rRNA sequencing, short-chain fatty acids (SCFAs) by gas chromatography-mass spectrometry analysis and neurotransmitters by liquid chromatograph mass spectrometry analysis.

RESULTS

Significantly higher systemic pro-inflammation, pro-oxidation and leaky gut biomarkers were observed in ScZ-Ag than NScZ-Ag group (all P<0.001). Compared to NScZ-Ag group, the alpha-diversity and evenness of fecal bacterial community were much lower, the abundance of fecal genera Prevotella was significantly increased, while that Bacteroides, Faecalibacterium, Blautia, Bifidobacterium,Collinsella and Eubacterium_coprostanoligenes were remarkably reduced in ScZ-Ag group (all corrected P<0.001). Meanwhile, 6 SCFAs and 6 neurotransmitters were much lower in ScZ-Ag group (all P<0.05). Finally, a few strongly positive or negative correlations among altered gut microbiota, SCFAs, systemic pro-inflammation, leaky gut, pro-oxidation and aggression severity were detected.

CONCLUSIONS

These results demonstrate that pro-inflammation, pro-oxidation and leaky gut phenotypes relating to enteric dysbacteriosis and microbial SCFAs feature the aggression onset or severity in ScZ individuals.

Associations between Omega-3 Index, Dopaminergic Genetic Variants and Aggressive and Metacognitive Traits: A Study in Adult Male Prisoners

Omega-3 long-chain polyunsaturated fatty acids (n-3 LCPUFA) are critical for cell membrane structure and function. Human beings have a limited ability to synthesise docosahexaenoic acid (DHA), the main n-3 LCPUFA required for neurological development. Inadequate levels of n-3 LCPUFA can affect the dopaminergic system in the brain and, when combined with genetic and other factors, increase the risk of developing aggression, inattention and impulse-control disorders. In this study, male prisoners were administered questionnaires assessing aggressive behaviour and executive functions. Participants also produced blood sampling for the measurement of the Omega-3 Index and the genotyping of dopaminergic genetic variants. Significant associations were found between functional genetic polymorphism in DBH rs1611115 and verbal aggression and between DRD2 rs4274224 and executive functions. However, the Omega-3 Index was not significantly associated with the tested dopaminergic polymorphisms. Although previous interactions between specific genotypes and n-3 LCPUFA were previously reported, they remain limited and poorly understood. We did not find any association between n-3 LCPUFA and dopaminergic polymorphisms in adult male prisoners; however, we confirmed the importance of genetic predisposition for dopaminergic genes (DBH and DRD2) in aggressive behaviour, memory dysfunction and attention-deficit disorder.

Imidacloprid and thiamethoxam affect synaptic transmission in zebrafish

Imidacloprid (IMI) and thiamethoxam (THM) are two commonly applied neonicotinoid insecticides. IMI and THM could cause negative impacts on non-target organisms like bees. However, the information about neurotoxicity of IMI and THM in fish is still scarce. Here we investigated the effects of IMI and THM on locomotor behavior, AChE activity, and transcription of genes related to synaptic transmission in zebrafish exposed to IMI and THM with concentrations of 50 ng L^-1 to 50,000 ng L^-1 at 14 day post fertilization (dpf), 21 dpf, 28 dpf and 35 dpf. Our results showed that IMI and THM significantly influenced the locomotor activity in larvae at 28 dpf and 35 dpf. THM elevated AChE activity at 28 dpf. The qPCR data revealed that IMI and THM affected the transcription of marker genes belonging to the synapse from 14 dpf to 35 dpf. Furthermore, IMI and THM mainly affected transcription of key genes in γ-aminobutyric acid, dopamine and serotonin pathways in larvae at 28 dpf and 35 dpf. These results demonstrated the neurotoxicity of IMI and THM in zebrafish. The findings from this study suggested that IMI and THM in the aquatic environment may pose potential risks to fish fitness and survival.