Biology subjects

Stahlhofer-Buss, T.

Publications and source records attributed to Stahlhofer-Buss, T..

4 recordsLinked to original sources

bioRxiv2024

Evaluation of behavioral and neurochemical changes induced by carbofuran in zebrafish (Danio rerio)

Carbofuran (CF) is a carbamate class pesticide, widely used in agriculture for pest control in crops. On the other hand, CF is also detected as a contaminant in food and water sources. This pesticide has high toxicity in non-target organisms, and its presence in the environment poses a threat to the ecosystem. Research has revealed that this pesticide acts as an inhibitor of acetylcholinesterase (AChE), inducing an accumulation of acetylcholine in the brain. Consequently, this leads to the emergence of a cholinergic syndrome and various detrimental effects on human health. Nonetheless, our understanding of CF impact on the central nervous system remains elusive. Therefore, this study aimed to investigate the effects of CF on behavioral and neurochemical parameters in adult zebrafish. The animals were exposed for 96 hours to different concentrations of CF (5, 50, and 500 {micro}g/L) and subjected to behavioral assessments in the novel tank test (NTT) and social preference test (SPT). Subsequently, they were euthanized, and their brains were used to evaluate neurochemical markers associated with oxidative stress and AChE levels. In the NTT and SPT, CF did not alter the evaluated behavioral parameters. Furthermore, CF did not affect the levels of AChE, non-protein sulfhydryl groups, and thiobarbituric acid reactive species in the zebrafish brain. However, further research is needed regarding the environmental exposure of this compound to non-target organisms.

neuroscience↗

bioRxiv2024

Exposure to epoxiconazole induces hyperlocomotion in adult zebrafish

Global agricultural production is sustained by an elevated use of pesticides. Their application in crops results in environmental contamination, which is demonstrated by widespread detections of these chemicals in aquatic ecosystems. This presence poses a risk to non-target organisms and ecological balance since the effects of potential exposure are misunderstood. Epoxiconazole (EPX) is a widely employed triazole fungicide, which has been frequently reported as a contaminant in superficial waters. However, the behavioral effects of EPX exposure in non-target organisms such as fish remain unexplored. We aimed to investigate the effects of EPX exposure on behavioral and biochemical outcomes, using zebrafish as a model organism. For this purpose, a static system was set with concentrations (24, 144, 240 g/L) based on the fungicide environmental detection. The novel tank test (NTT) was performed after 96 h of exposure. The social preference test (SPT) was executed after 120 h, as well as the biochemical assays. In the NTT, the animals increased distance traveled, crossings, entries in the top area, and mean speed, indicating hyperlocomotion. No significant effects were observed in the SPT and the biochemical analyses. We suggest that the increased locomotion is related to the stimulant properties of EPX. Our results contribute to an in-depth understanding of this fungicide effects in zebrafish, which is essential for environmental contamination monitoring and management.

neuroscience↗

bioRxiv2023

N-acetylcysteine and acetyl-L-carnitine did not prevent acute PTZ-induced seizure in adult and larvae zebrafish

Epilepsy is a prevalent neurological disorder, affecting approximately 1 to 2% of the global population. The hallmark of epilepsy is the occurrence of epileptic seizures, which are characterized by predictable behavioral changes reflecting the underlying neural mechanisms of the disease. Unfortunately, around 30% of patients do not respond to the current available pharmacological treatments. Consequently, it is crucial to explore alternative therapeutic options for managing these seizures. Two potential candidates for attenuating seizures are N-acetylcysteine (NAC) and Acetyl-L-carnitine (ALC), as they have shown promising neuroprotective effects through the modulation of the neurotransmitter glutamate. Therefore, this study aims to assess the effects of varying concentrations (0.1, 1.0, and 10 mg/L) of NAC and ALC on acute PTZ-induced seizures in zebrafish, in both adult and larval stages. The evaluation of behavioral parameters such as seizure intensity and latency to the crisis can provide insights into the efficacy of these substances. However, our results indicate that both drugs at any of the tested concentrations were not able to reduce PTZ-induced epileptic seizures. On the other hand, the administration of diazepam demonstrated a notable reduction in seizure intensity and an increase in latencies to higher scores of epileptic seizures. Consequently, we conclude that, under the conditions employed in this study, NAC and ALC do not exhibit any significant effects on acute seizures in zebrafish.

neuroscience↗

bioRxiv2023

Chemically-induced epileptic seizures in zebrafish: a systematic review

The use of zebrafish as a model organism is gaining evidence in the field of epilepsy as it may help to understand the mechanisms underlying epileptic seizures. As zebrafish assays became popular, the heterogeneity between protocols increased, making it hard to choose a standard protocol to conduct research while also impairing the comparison of results between studies. We conducted a systematic review to comprehensively profile the chemically-induced seizure models in zebrafish. Literature searches were performed in PubMed, Scopus and Web of Science, followed by a two-step screening process based on inclusion/exclusion criteria. Qualitative data were extracted and a sample of 100 studies was randomly selected for risk of bias assessment. Out of the 1058 studies identified after removing duplicates, 201 met the inclusion criteria. We found that the most common chemoconvulsants used in the reviewed studies were pentylenetetrazole (n = 180), kainic acid (n = 11), and pilocarpine (n = 10), which increase seizure severity in a dose-dependent manner. The main outcomes assessed were seizure scores and locomotion. Significant variability between the protocols was observed for administration route, duration of exposure, and dose/concentration. Of the studies subjected to risk of bias assessment, most were rated as low risk of bias for selective reporting (94%), baseline characteristics of the animals (67%), and blinded outcome assessment (54%). Randomization procedures and incomplete data were rated as unclear in 81% and 68% of the studies, respectively. None of the studies reported the sample size calculation. Overall, these findings underscore the need for improved methodological and reporting practices to enhance reproducibility and reliability of zebrafish models for studying epilepsy. Our study offers a comprehensive overview of the current state of chemically-induced seizure models in zebrafish, highlighting the common chemoconvulsants used and the variability in protocol parameters. This may be particularly valuable to researchers interested in understanding the underlying mechanisms of epileptic seizures and screening potential drug candidates in zebrafish models. HIGHLIGHTS- We systematically reviewed the effects of chemically-induced seizures in zebrafish; - PTZ is the most used epileptic seizure inducer in zebrafish; - More than 50% of the studies fail to report data such as outlier exclusion criteria and sample size estimation; - The results showed a need for better standardization of protocols.

neuroscience↗