Taurine-mediated aggression is abolished via 5-HT1A antagonism and serotonin depletion in zebrafish

Environmental pollution of paraben needs attention: A study of methylparaben and butylparaben co-exposure trigger neurobehavioral toxicity in zebrafish

Parabens (PBs) are commonly utilized as preservatives in various commodities. Of all the PBs, methylparaben (MeP) and butylparaben (BuP) are usually found together at similar levels in the aqueous environment. Although a few studies have demonstrated that PBs are neurotoxic when present alone, the neurobehavioral toxic effects and mechanisms of coexisting MeP and BuP at environmental levels has not been determined. Neurobehavior is a sensitive indicator for identifying neurotoxicity of environmental pollutants. Therefore, adult female zebrafish (Danio rerio) were chronic co-exposure of MeP and BuP at environmental levels (5, 50, and 500 ng/L) for 60 d to investigate the effects on neurobehavior, histopathology, oxidative stress, mitochondrial function, neurotransmitters and gene expression. The results demonstrated that chronic co-exposure of MeP and BuP interfered with several behaviors (learning-memory, anxiety, fear, aggressive and shoaling behavior) in addition to known mechanisms of producing oxidative stress and disrupting energy. More intriguingly, chronic co-exposure of MeP and BuP caused retinal vacuolization and apoptosis in the optic tectum zone. It even has further effects on the phototransduction pathway, impairing optesthesia and leading to neurotransmitters dysregulation. These are critical underlying mechanisms resulting in neurobehavioral abnormalities. This study confirms that the pollution of multiple PBs by chronic co-exposure in aquatic environments can result neurobehavioral toxicity. It also suggests that the prolonged effects of PBs on aquatic ecosystems and health require close attention.

Plasma taurine level is linked to symptom burden and clinical outcomes in post-COVID condition

BACKGROUND

A subset of individuals (10-20%) experience post-COVID condition (PCC) subsequent to initial SARS-CoV-2 infection, which lacks effective treatment. PCC carries a substantial global burden associated with negative economic and health impacts. This study aims to evaluate the association between plasma taurine levels with self-reported symptoms and adverse clinical outcomes in patients with PCC.

METHODS AND FINDINGS

We analyzed the plasma proteome and metabolome of 117 individuals during their acute COVID-19 hospitalization and at the convalescence phase six-month post infection. Findings were compared with 28 age and sex-matched healthy controls. Plasma taurine levels were negatively associated with PCC symptoms and correlated with markers of inflammation, tryptophan metabolism, and gut dysbiosis. Stratifying patients based on the trajectories of plasma taurine levels during six-month follow-up revealed a significant association with adverse clinical events. Increase in taurine levels during the transition to convalescence were associated with a reduction in adverse events independent of comorbidities and acute COVID-19 severity. In a multivariate analysis, increased plasma taurine level between acute and convalescence phase was associated with marked protection from adverse clinical events with a hazard ratio of 0.13 (95% CI: 0.05-0.35; p<0.001).

CONCLUSIONS

Taurine emerges as a promising predictive biomarker and potential therapeutic target in PCC. Taurine supplementation has already demonstrated clinical benefits in various diseases and warrants exploration in large-scale clinical trials for alleviating PCC.

Involvement of the serotoninergic system in the anxiolytic action mechanism of a liposomal formulation containing nimodipine (NMD-Lipo)

In the search for anxiolytic drugs with fewer adverse effects, calcium blockers were proposed as a benzodiazepines (BZDs) alternative. In this context, the anxiolytic effect of nimodipine has been demonstrated. However, its low bioavailability and solubility could be improved by using nanostructured drug delivery systems such as liposomes. In this way, liposomal formulation containing nimodipine (NMD-Lipo) was developed. The NMD-lipo is a formulation capable of improving the kinetic characteristics of the drug, as well as the anxiolytic effect of nimodipine. In this work, the serotonergic system participation in the anxiolytic mechanism of the liposomal formulation containing nimodipine (NMD-Lipo) was investigated. A possible 5-HT1A receptor mediation on the NMD-Lipo anxiolytic effect was demonstrated by using WAY 100635 (5-HT1A receptor antagonist) since the antagonist reversed the NMD-Lipo anxiolytic effect in the light/dark test and elevated plus maze test. The results demonstrated that the NMD-Lipo administration had anxiolytic activity through 5-HT1A receptors without causing sedation or compromising the motor coordination of the tested animals.

Dietary Taurine Intake Affects the Growth Performance, Lipid Composition, and Antioxidant Defense of Juvenile Ivory Shell (Babylonia areolata)

In this study, an eight-week feeding trial was performed to investigate the effects of different taurine supplementation levels (0.0% as control, 1.0%, 1.5%, 2.0%, 2.5%, and 3.0%) on the growth performance, lipid composition, and antioxidant ability in juvenile ivory shells Babylonia areolata. The results showed that taurine supplementation significantly improved the specific growth rates (SGRs) and survival rates of ivory shell (except the survival rate in the 3.0% taurine diet group) (p < 0.05). The SGRs showed an increasing and then decreasing tendency with increasing dietary taurine supplementation, and the highest value was observed in the 2.0% taurine diet (2.60%/d). The taurine content in the muscle of ivory shells fed taurine-supplemented diets significantly increased when compared to the control group (p < 0.05). The profiles of C22:2n6 in the muscle of ivory shells fed taurine-supplemented diets were significantly higher than in the control group (p < 0.05), and the highest values were observed in the 2.0% taurine supplementation group. The high-density lipoprotein cholesterol (HDL-C) content in the hepatopancreas showed an increasing and then decreasing tendency with increasing dietary taurine supplementation, while the low-density lipoprotein cholesterol (LDL-C) concentration showed a decreasing tendency. Furthermore, the activities of pepsin and lipase in both the intestine and hepatopancreas significantly increased at moderate taurine supplementation levels compared to the control group (p < 0.05). Accordingly, obvious increases in the histological parameters in the intestine of ivory shells fed taurine-supplemented diets were also found. As for the antioxidant ability, the activities of the total antioxidant capacity (T-AOC) and superoxide dismutase (SOD) showed an increasing and then decreasing tendency with increasing dietary taurine supplementation, and the highest values were observed in the 1.0% and 1.0-2.0% taurine supplementation groups, respectively; the malondialdehyde (MDA) contents significantly decreased with increasing dietary taurine supplementation (p < 0.05). The taurine intake affected the expression of four appetite-related genes in the hepatopancreas, in which orexin and NPY showed an increasing and then decreasing tendency, while leptin and cholecyatoklnin decreased with increasing dietary taurine supplementation. In conclusion, moderate taurine supplementation in an artificial diet (about 1.5-2.0%) could improve the growth performance and antioxidant ability and change the lipid composition of juvenile ivory shells.

Brain metabolite profiles provide insight into mechanisms for behavior sexual dimorphisms in zebrafish (Danio rerio)

The zebrafish (Danio rerio) has historically been a useful model for research in genetics, ecology, biology, toxicology, and neurobehavior. Zebrafish have been demonstrated to have brain sexual dimorphism. However, the sexual dimorphism of zebrafish behavior demands our attention, particularly. To evaluate the behavior and brain sexual dimorphisms in zebrafish, this study assessed sex differences in adult D. rerio in four behavioral domains, including aggression, fear, anxiety, and shoaling, and further compared with metabolites in the brain tissue of females and males. Our findings showed that aggression, fear, anxiety and shoaling behaviors were significantly sexually dimorphic. Interestingly, we also show through a novel data analysis method, that the female zebrafish exhibited significantly increased shoaling behavior when shoaled with male zebrafish groups and, for the first time, we offer evidence that male shoals are beneficial in dramatically alleviating anxiety in zebrafish. In addition, there were significant changes in metabolites in zebrafish brain tissue between the sexes. Furthermore, zebrafish behavioral sexual dimorphism may be associated with brain sexual dimorphism, with significant differences in brain metabolites. Therefore, to prevent the influence or even bias of behavioral sex differences on results, it is suggested that behavioral studies or behavioral-based other relevant investigations consider sexual dimorphism of behavior and brain.

Buspirone, a 5-HT1A agonist attenuates social isolation-induced behavior deficits in rats: a comparative study with fluoxetine

Social isolation is a potent stressor in both humans and animals that results in increased anger-like emotion, (anger in humans), aggression and suicidal ideation in humans [suicidal trait-related behavior in rats (STRB)]. The study's purpose was to compare the effects of buspirone (BUS) and fluoxetine (Flx) on social isolation-induced behavior deficits in rats. The male Wistar rats were randomized into six groups and caged individually for 14 days except for the non stress control (nSC) group. They were then divided into the following groups, stress control (SC), Flx (30), BUS (10), BUS (20) and BUS (40) and treated from day 14 to day 28. On the last day of treatment behavior parameters were recorded. Serum cortisol, blood pressure (BP) measurement, magnetic resonance imaging (MRI) of the rat's brain and brain-derived neurotrophic factor (BDNF) expression were performed. SC group showed a significant increase in anger-like emotion, aggression, irritability score, learned helplessness, increased cortisol level and reduced BDNF. These behavioral deficits were attenuated by BUS and Flx, Both were found to be equally beneficial in preventing anger-like emotions and aggression. Flx, which has been found to promote suicidal thoughts in people, did not reduce irritability in rats, showing that it did not affect it. BUS significantly improved all behavioral traits also reduced cortisol levels, significantly increased BDNF and normalized BP. Neuroimaging studies in SC brains showed a reduction in amygdala size compared to nSC, BUS treatment mitigated this reduction. Buspirone is effective in preventing social isolation induced behavioural-deficits.

The Neurobiology of Behavior and Its Applicability for Animal Welfare: A Review

Simple Summary

Animal welfare is the result of physical and psychological well-being and is expected to occur if animals are free: (1) from hunger, thirst and malnutrition, (2) from discomfort, (3) from pain, (4) to express normal behavior, and (5) from fear and distress. Nevertheless, well-being is not a constant state but rather the result of certain brain dynamics underlying innate motivated behaviors and learned responses. Thus, by understanding the foundations of the neurobiology of behavior we fathom how emotions and well-being occur in the brain. Herein, we discuss the potential applicability of this approach for animal welfare. First, we provide a general view of the basic responses coordinated by the central nervous system from the processing of internal and external stimuli. Then, we discuss how those stimuli mediate activity in seven neurobiological systems that evoke innate emotional and behavioral responses that directly influence well-being and biological fitness. Finally, we discuss the basic mechanisms of learning and how it affects motivated responses and welfare.

Abstract

Understanding the foundations of the neurobiology of behavior and well-being can help us better achieve animal welfare. Behavior is the expression of several physiological, endocrine, motor and emotional responses that are coordinated by the central nervous system from the processing of internal and external stimuli. In mammals, seven basic emotional systems have been described that when activated by the right stimuli evoke positive or negative innate responses that evolved to facilitate biological fitness. This review describes the process of how those neurobiological systems can directly influence animal welfare. We also describe examples of the interaction between primary (innate) and secondary (learned) processes that influence behavior.