Characterization of the cystine/glutamate antiporter in cultured Bergmann glia cells

Phenolic constituents isolated from Senna tora sprouts and their neuroprotective effects against glutamate-induced oxidative stress in HT22 and R28 cells

The consumption of sprouts has been steadily increasing due to their being an excellent source of nutrition. It is known that the bioactive constituents of legumes can be increased after germination. In this study, the extract from Senna tora sprouts is shown to exhibit improved radical scavenging activities and better neuroprotective effects in HT22 hippocampal neuronal (HT22) and R28 retina precursor (R28) cells than those from seeds due to an increased content of phenolic constituents, especially compounds 1 and 3-6. A phytochemical investigation of S. tora sprouts resulted in the isolation of two new naphthopyrone glycosides (1-2) with 27 previously reported compounds. Their structures were determined via interpreting spectroscopic data. Compounds 1 and 3-6 were found to possess radical scavenging activities and neuroprotective effects against oxidative stress in both neuronal cells. Hence, Senna tora sprouts and their constituents may be developed as natural neuroprotective agents via antioxidative effects.

Nanomaterials-Based Electrochemical Sensors for In Vitro and In Vivo Analyses of Neurotransmitters

Neurotransmitters are molecules that transfer chemical signals between neurons to convey messages for any action conducted by the nervous system. All neurotransmitters are medically important; the detection and analysis of these molecules play vital roles in the diagnosis and treatment of diseases. Among analytical strategies, electrochemical techniques have been identified as simple, inexpensive, and less time-consuming processes. Electrochemical analysis is based on the redox behaviors of neurotransmitters, as well as their metabolites. A variety of electrochemical techniques are available for the detection of biomolecules. However, the development of a sensing platform with high sensitivity and selectivity is challenging, and it has been found to be a bottleneck step in the analysis of neurotransmitters. Nanomaterials-based sensor platforms are fascinating for researchers because of their ability to perform the electrochemical analysis of neurotransmitters due to their improved detection efficacy, and they have been widely reported on for their sensitive detection of epinephrine, dopamine, serotonin, glutamate, acetylcholine, nitric oxide, and purines. The advancement of electroanalytical technologies and the innovation of functional nanomaterials have been assisting greatly in in vivo and in vitro analyses of neurotransmitters, especially for point-of-care clinical applications. In this review, firstly, we focus on the most commonly employed electrochemical analysis techniques, in conjunction with their working principles and abilities for the detection of neurotransmitters. Subsequently, we concentrate on the fabrication and development of nanomaterials-based electrochemical sensors and their advantages over other detection techniques. Finally, we address the challenges and the future outlook in the development of electrochemical sensors for the efficient detection of neurotransmitters.

The neurotoxin diethyl dithiophosphate impairs glutamate transport in cultured Bergmann glia cells

Glutamate, the main excitatory neurotransmitter in the vertebrate Central Nervous System, is involved in almost every aspect of brain physiology, and its signaling properties are severely affected in most neurodegenerative diseases. This neurotransmitter has to be efficiently removed from the synaptic cleft in order to prevent an over-stimulation of glutamate receptors that leads to neuronal death. Specific sodium-dependent membrane transporters, highly enriched in glial cells, elicit the clearance of glutamate. Once internalized, it is metabolized to glutamine by the glia-enriched enzyme Glutamine synthetase. Accumulated glutamine is released into the extracellular space for its uptake into pre-synaptic neurons and its conversion to glutamate that is packed into synaptic vesicles completing the glutamate/glutamine cycle. Diverse chemical compounds, like organophosphates, directly affect brain chemistry by altering levels of neurotransmitters in the synaptic cleft. Organophosphate compounds are widely used as pesticides, and all living organisms are continuously exposed to these substances, either in a direct or indirect manner. Its metabolites, like the diethyl dithiophosphate, are capable of causing brain damage through diverse mechanisms including perturbation of neuronal-glial cell interactions and have been associated with attention-deficit disorders and other mental illness. In order to characterize the neurotoxic mechanisms of diethyl dithiophosphate, we took advantage of the well characterized model of chick cerebellar Bergmann glia cultures. A significant impairment of [³H] d-Aspartate transport was found upon exposure to the metabolite. These results indicate that glia cells are targets of neurotoxic substances such as pesticides and that these cells might be critically involved in the associated neuronal death.