Functional assays flux

Schmalhofer WA, Swensen AM, Thomas BS et al (2010) A pharmacologically validated, high-capacity, functional thallium flux assay for the human Ether-a-go-go related gene potassium channel. Assay Drug Dev Technol 8(6) 714-726... 

Keywords Recombinant human receptors Functional assays Altinicline Nicotine Parkinson s disease nAChR subtypes Nicotinic acetylcholine receptors Nicotine flux . SIB-1765F Cognitive deficits... 

Reconstitutions are technically simple, require little training, and teach you how to handle detergents, phospholipids, membranes, and membrane proteins. Once the reconstitution has succeeded, you can observe your protein in a defined environment, free of influences from the cell metabolism. Afterward, you can construct in vitro entire metabolic chains or processes and thus build your own organelle. Sometimes reconstitution of the translocator function and flux assay is a prerequisite to the purification of the translocator protein. Figure 4.2 shows the possibilities of this field. 

To illustrate the role of passive influx in transport assays, we plotted the flux ratio Jp, a/Ja b as a function of the passive flux ((b). Passive flux varies enormously... 

Key words Cardiotoxicity, In vitro assays for cardiotoxicity, Cardiac safety, Functional flux assays, Fluorescence-based assays, hERG, Patch clamp, Alternative tests, Microelectrode array, hESC-derived cardiomyocytes, FLIPER, Q-T interval, HEK 293, CHO, Embryonic stem cells, Differentiation, hiPSCs, Drug interaction, Safety pharmacology, ICH guidelines, Arrhythmia... 

Our preliminary results with fish brain preparations suggest that ion flux techniques may be valuable in studies of target site differences between species. We have demonstrated veratridine-stimulated, tetrodotoxin-sensitive sodium uptake in a vesicular preparation from fish brain, thus confirming the presence of functional sodium channels in this preparation. Our results with , -DDT in this system also agree well with the action of DDT analogs and pyrethroids in mouse brain assays. Further studies wih both preparations should allow the exploration of target site differences between mammals and fish that have been inferred from whole animal toxicity studies. 

Finally, it is possible that these techniques can be extended successfully to insect CNS preparations. Methods now exist to prepare functional insect synaptosomes from insect ganglia (1 ), and these preparations have been used to demonstrate veratridine-dependent neurotransmitter release and enhancement of this release by deltamethrin in a superfusion assay (2j)). Further refinement of these methods should allow direct measurement of sodium channel-mediated sodium fluxes in insect CNS preparations, thus allowing the investigation of target site differences not only between mammals and insects but also between susceptible and resistant insect strains. 

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