Amygdala Underlies the Environment Dependency of Defense Responses Induced via Superior Colliculus

In our previous study, we showed that the defense responses induced by the selective optogenetic activation of the uncrossed output pathway from the deeper layer of the superior colliculus were environment dependent in the mouse. In a small closed box, the stimulus frequently induced flight (fast forward run away) responses, while in a large open field, the stimulus tended to induce backward retreat responses. We tested a hypothesis that the amygdala is involved in such environment dependency of the innate defense responses. For this purpose, we made a bilateral lesion of the amygdala induced by the ibotenic acid injections in male mice. As a result, in the mice with lesions of substantial portions of the basolateral and basomedial complex, the flight responses in the closed box disappeared and retreat responses were mainly induced. The retreat responses on the open platform were unchanged. Classically, the amygdala has been considered to be involved in the memory-dependent contextual modulation of the fear responses. In contrast, the present results suggest a novel view on the role of the amygdala in which the amygdala plays a key role in sensing the current environmental setting for making a quick decision of action upon emergency, which is critical for survival in the natural environment.

A human stem cell-derived test system for agents modifying neuronal N-methyl-d-aspartate-type glutamate receptor Ca2+-signalling

Methods to assess neuronal receptor functions are needed in toxicology and for drug development. Human-based test systems that allow studies on glutamate signalling are still scarce. To address this issue, we developed and characterized pluripotent stem cell (PSC)-based neural cultures capable of forming a functional network. Starting from a stably proliferating neuroepithelial stem cell (NESC) population, we generate “mixed cortical cultures” (MCC) within 24 days. Characterization by immunocytochemistry, gene expression profiling and functional tests (multi-electrode arrays) showed that MCC contain various functional neurotransmitter receptors, and in particular, the N-methyl-d-aspartate subtype of ionotropic glutamate receptors (NMDA-R). As this important receptor is found neither on conventional neural cell lines nor on most stem cell-derived neurons, we focused here on the characterization of rapid glutamate-triggered Ca2+ signalling. Changes of the intracellular free calcium ion concentration ([Ca2+]i) were measured by fluorescent imaging as the main endpoint, and a method to evaluate and quantify signals in hundreds of cells at the same time was developed. We observed responses to glutamate in the low µM range. MCC responded to kainate and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), and a subpopulation of 50% had functional NMDA-R. The receptor was modulated by Mg2+, Zn2+ and Pb2+ in the expected ways, and various toxicologically relevant agonists (quinolinic acid, ibotenic acid, domoic acid) triggered [Ca2+]i responses in MCC. Antagonists, such as phencyclidine, ketamine and dextromethorphan, were also readily identified. Thus, the MCC developed here may fill an important gap in the panel of test systems available to characterize the effects of chemicals on neurotransmitter receptors.

Human Poisoning from Poisonous Higher Fungi: Focus on Analytical Toxicology and Case Reports in Forensic Toxicology

Several families of higher fungi contain mycotoxins that cause serious or even fatal poisoning when consumed by humans. The aim of this review is to inventory, from an analytical point of view, poisoning cases linked with certain significantly toxic mycotoxins: orellanine, α- and β-amanitin, muscarine, ibotenic acid and muscimol, and gyromitrin. Clinicians are calling for the cases to be documented by toxicological analysis. This document is therefore a review of poisoning cases involving these mycotoxins reported in the literature and carries out an inventory of the analytical techniques available for their identification and quantification. It seems indeed that these poisonings are only rarely documented by toxicological analysis, due mainly to a lack of analytical methods in biological matrices. There are many reasons for this issue: the numerous varieties of mushroom involved, mycotoxins with different chemical structures, a lack of knowledge about distribution and metabolism. To sum up, we are faced with (i) obstacles to the documentation and interpretation of fatal (or non-fatal) poisoning cases and (ii) a real need for analytical methods of identifying and quantifying these mycotoxins (and their metabolites) in biological matrices.

Toxicological and pharmacological profile of Amanita muscaria (L.) Lam. – a new rising opportunity for biomedicine

Amanita muscaria, commonly known as fly agaric, is a basidiomycete. Its main psychoactive constituents are ibotenic acid and muscimol, both involved in ‘pantherina-muscaria’ poisoning syndrome. The rising pharmacological and toxicological interest based on lots of contradictive opinions concerning the use of Amanita muscaria extracts’ neuroprotective role against some neurodegenerative diseases such as Parkinson’s and Alzheimer’s, its potent role in the treatment of cerebral ischaemia and other socially significant health conditions gave the basis for this review. Facts about Amanita muscaria’s morphology, chemical content, toxicological and pharmacological characteristics and usage from ancient times to present-day’s opportunities in modern medicine are presented.

Natural Products Extracted from Fungal Species as New Potential Anti-Cancer Drugs: A Structure-Based Drug Repurposing Approach Targeting HDAC7

Mushrooms can be considered a valuable source of natural bioactive compounds with potential polypharmacological effects due to their proven antimicrobial, antiviral, antitumor, and antioxidant activities. In order to identify new potential anticancer compounds, an in-house chemical database of molecules extracted from both edible and non-edible fungal species was employed in a virtual screening against the isoform 7 of the Histone deacetylase (HDAC). This target is known to be implicated in different cancer processes, and in particular in both breast and ovarian tumors. In this work, we proposed the ibotenic acid as lead compound for the development of novel HDAC7 inhibitors, due to its antiproliferative activity in human breast cancer cells (MCF-7). These promising results represent the starting point for the discovery and the optimization of new HDAC7 inhibitors and highlight the interesting opportunity to apply the “drug repositioning” paradigm also to natural compounds deriving from mushrooms.

ALZHEIMER’S DISEASE: EXPERIMENTAL AND CLINICAL RESEARCHES OF CHINESE HERBAL MEDICINE NEUROBIOLOGICAL EFFECTS (A REVIEW)

В обзоре представлен анализ экспериментальных и клинических данных по исследованию нейробиологических эффектов сборов лекарственных веществ, которые используют в терапии болезни Альцгеймера в китайской медицине. В качестве экспериментальных моделей болезни Альцгеймера использовали крыс, которым вводили пептиды A β1-42 или A β25-35, иботеновую кислоту, стрептозотоцин, а также естественную линию мышей SAMP 8 с фенотипом ускоренного старения и др. Природные вещества, входящие в сборы, продемонстрировали разные нейробиологические эффекты в клетках гиппокампа - ингибировали отложения бета-амилоида, увеличивали число нейронов с относительно регулярной морфологией клеток и уменьшали число апоптозных клеток, уменьшали продукцию индуцибельной NO -синтазы ( iNOS ), снижали уровень реактивной экспрессии RAGE и повышали уровень реактивной экспрессии LRP -1, снижали фосфорилирование τ-белка на участках Thr 231 и Ser 422, ингибировали экспрессию τ-протеинкиназ GSK -3βи CDK -5, уменьшали процессы активации и воспаления микроглии, продуцировали в церебральных кортикальных слоях 15 видов N -гликанов, которые у экспериментальных животных отсутствовали. Было отмечено также улучшение процессов запоминания и обучения. The analysis of experiments and clinical data about research of neurobiological effects of chinese herbal medicine, which is used by Alzheimer`s disease treatment, was presented in given overview. The rats with injection of A β1-42 or A β25-35 peptides, or ibotenic acid, or streptozotocin as well as the natural line of mice SAMP 8 with the phenotype of accelerated aging and other were used as the experimental models of Alzheimer`s disease. Various neurobiological effects of various herbal decoctions in the cells of hippocampus were demonstrated - the inhibition of amyloid β peptides aggregation, increasing of neurons quantity with normal morphology and decreasing of apoptotic cells, decreasing of inducible nitric oxide synthase ( iNOS ) production, decreasing of reactive expression level of RAGE and increasing reactive expression level of LRP -1, decreasing of tau protein phosphorylation at Thr 231 and Ser 422, inhibition of expression of GSK -3β and CDK -5, decreasing of activation and inflammation of microglia, production of 15 types of N -glycans in the cerebral cortex layers, which are absent in experimental animals. The improvement of memorization and training abilities was established.