Commentary: Establishing zebrafish as a model to study the anxiolytic effects of scopolamine

Betanin mitigates scopolamine-induced cognitive impairment by restoring cholinergic function, boosting brain antioxidative status, and increasing BDNF level in the zebrafish model

Betalains obtained from Beta vulgaris (family Caryophyllales) are regularly consumed as part of the regular diet with medicinal benefits due to antioxidant and anti-inflammatory properties. The objective of this article was to evaluate betanin's neuroprotective properties in a scopolamine-induced zebrafish paradigm. Betanin (BET) (50, 100, and 200 mg/L), and donepezil (10 mg/L) were delivered to zebrafish in a treatment tank once a day for 8 days, while memory impairment was produced by scopolamine (100 µM), which was given 60 min before behavioral assessments. The treatment dosages were determined based on acute toxicity studies. The existence of betacyanin and betaxanthins of BET was tested using liquid chromatography-mass spectrometry (LC-MS). The Y-maze task was used to examine the novelty and spatial memory, while the novel tank diving test was used to assess anxiety-like behavior (NTT). The activities of acetylcholinesterase (AChE) and the oxidative stress sensitivity in zebrafish brains were examined. Also, brain-derived neurotrophic factor (BDNF) level is quantified by an ELISA kit. Scopolamine-induced rises in AChE activity, memory loss, anxiety, and brain oxidant capacity were all reduced by BET. These results suggest that BET (50 and 100 mg/L) has a therapeutic ability to treat brain oxidative stress and cognitive deficits in amnesic zebrafish.

Sex differences shape zebrafish performance in a battery of anxiety tests and in response to acute scopolamine treatment

Sex differences influence human and animal behavioral and pharmacological responses. The zebrafish (Danio rerio) is a powerful, popular model system in neuroscience and drug screening. However, the impact of zebrafish sex differences on their behavior and drug responses remains poorly understood. Here, we evaluate baseline anxiety-like behavior in adult male and female zebrafish, and its changes following an acute 30-min exposure to 800-μM scopolamine, a common psychoactive anticholinergic drug. Overall, we report high baseline anxiety-like behavior and more individual variability in locomotion in female zebrafish, as well as distinct, sex-specific (anxiolytic-like in females and anxiogenic-like in males) effects of scopolamine. Collectively, these findings reinforce the growing importance of zebrafish models for studying how both individual and sex differences shape behavioral and pharmacological responses.

β-glucan and anisodamine can enhance the immersion immune efficacy of inactivated cyprinid herpesvirus 2 vaccine in Carassius auratus gibelio

As one of the most important fish in freshwater aquaculture, gibel carp (Carassius auratus gibelio) is easily susceptible to Cyprinid herpesvirus 2 (CyHV-2). Immersion vaccination has attracted many researchers due to its simple operation in preventing infectious diseases. However, the unavoidable disadvantage is that the immersion vaccine must be used with adjuvants to get a better performance. In this study, gibel carps were vaccinated by a 60 min bath in a β-propiolactone-inactivated Cyprinid herpesvirus 2, mixed with DTT, β-glucan, anisodamine and scopolamine, respectively. After immunization, the fishs were challenged by CyHV-2 in 2 weeks. By analyzing pathological section, we found that β-glucan, anisodamine and scopolamine groups protected the gibel carp compared to the control group, which was consistent with the trend of survival rate. Specifically, β-glucan group in serum appeared best on lysozyme, TSOD and complement C3. Real time quantitative RT-PCR results demonstrated that in both spleen and head kidney tissues, mRNA expressions of typical Th1 immune response cytokines IL-2 and IFN-γ2 in β-glucan group and anisodamine group were significantly higher than other groups and the level of immunoglobulins related to systemic immunity (IgM) and mucosal immunity (IgZ) were also enhanced in the immune period. DTT group slightly affected immune gene and serum enzyme activity, while did not show an adjuvant effect on survival rate. In addition, four adjuvant groups could obviously inhibit CyHV-2 replication. This study explored and proved the good efficiency of β-glucan or anisodamine as immersion immune adjuvant and also provided reference for improving the efficiency of immersion immunity.

Understanding Central Nervous System Effects of Deliriant Hallucinogenic Drugs through Experimental Animal Models

Hallucinogenic drugs potently alter human behavior and have a millennia-long history of use for medicinal and religious purposes. Interest is rapidly growing in their potential as CNS modulators and therapeutic agents for brain conditions. Antimuscarinic cholinergic drugs, such as atropine and scopolamine, induce characteristic hyperactivity and dream-like hallucinations and form a separate group of hallucinogens known as "deliriants". Although atropine and scopolamine are relatively well-studied drugs in cholinergic physiology, deliriants represent the least-studied class of hallucinogens in terms of their behavioral and neurological phenotypes. As such, novel approaches and new model organisms are needed to investigate the CNS effects of these compounds. Here, we comprehensively evaluate the preclinical effects of deliriant hallucinogens in various animal models, their mechanisms of action, and potential interplay with other signaling pathways. We also parallel experimental and clinical findings on deliriant agents and outline future directions of translational research in this field.