Evaluation of toxicity equivalent factors of paralytic shellfish poisoning toxins in seven human sodium channels types by an automated high throughput electrophysiology system
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Although voltage-gated sodium channels (Na v ) are the cellular target of paralytic shellfish poisoning (PSP) toxins and that patch clamp electrophysiology is the most effective way of studying direct interaction of molecules with these channels, nowadays, this technique is still reduced to more specific analysis due to the difficulties of transforming it in a reliable throughput system. Actual functional methods for PSP detection are based in binding assays using receptors but not functional Na v channels. Currently, the availability of automated patch clamp platforms and also of stably transfected cell lines with human Na v channels allow us to introduce this specific and selective method for fast screenings in marine toxin detection. Taking advantage of the accessibility to pure PSP standards, we calculated the toxicity equivalent factors (TEFs) for nine PSP analogs obtaining reliable TEFs in human targets to fulfill the deficiencies of the official analytic methods and to verify automated patch clamp technology as a fast and reliable screening method for marine toxins that interact with the sodium channel. The main observation of this work was the large variation of TEFs depending on the channel subtype selected, being remarkable the variation of potency in the 1.7 channel subtype and the suitability of Na v 1.6 and 1.2 channels for PSP screening.
KeywordsParalytic shellfish poisoning Automated patch clamp Sodium channels Saxitoxin
The research leading to these results has received funding from the following FEDER cofounded-grants. From CDTI and Technological Funds, supported by Ministerio de Economía y Competitividad, AGL2012-40185-CO2-01 and Consellería de Cultura, Educación e OrdenaciónUniversitaria, GRC2013-016, and through AxenciaGalega de Innovación, Spain, ITC-20133020 SINTOX, IN852A 2013/16-3 MYTIGAL. From CDTI under ISIP Programme, Spain, IDI-20130304 APTAFOOD. From the European Union’s Seventh Framework Programme managed by REA—Research Executive Agency (FP7/2007–2013) under Grant Agreement Nos. 265409 µAQUA, 315285 CIGUATOOLS, and 312184 PHARMASEA.
Conflict of interest
The authors declare that they have no conflict of interest.
- AOAC (1990) Paralytic shellfish poison. Biological method. Final action. In: Hellrich EBK (ed) Official methods of analysis. Association of Official Methods of Analytical Chemists, Arlington, VA, pp 881–882Google Scholar
- AOAC (2005) Method 2005.06: Paralytic shellfish poisoning toxins in shellfish. Prechromatographic oxidation and liquid chromatography with fluorescence detection. Official Methods of Analysis of the Association of Official Analytical Chemists., Method 2005.06, First Action.) (Commission, E. (2006). Commission Regulation (EC) No 1664/2006 of 6 November 2006 amending Regulation (EC) No 2074/2005 as regards implementing measures for certain products of animal origin intended for human consumption and repealing certain implementing measures. Off J Eur Union L 320:13–45Google Scholar
- AOAC (2011a) AOAC Official method 2011.02 Determination of paralytic shellfish poisoning toxins in mussels, clams, oysters and scallops. Post-column oxidation method (PCOX). First action 2011. In MD Official Methods of Analysis of the AOAC (Association of Official Analytical Chemists) Gaithersburg, USA, Method 2011.02Google Scholar
- AOAC (2011b) AOAC official method 2011.27. In Paralytic shellfish toxins (PSTs) in shellfish, receptor binding assay. Association of Official Methods of Analytical Chemists, Arlington, VA; AOAC International: AOAC International, Gaithersburg, MD), pp 881–882Google Scholar
- Botana LM (ed) (2014) Seafood and freshwater toxins. Pharmacology, physiology and detection, 3rd ed. CRC Press, Boca RatonGoogle Scholar
- EFSA (2009a) Scientific opinion of the panel on contaminants in the food chainon: a request from the European Commission on marine biotoxins in shellfish: saxitoxin group (question no EFSA-Q-2006-065E). EFSA J 1019:1–76Google Scholar
- EFSA (2009b) Scientific opinion on marine biotoxins in shellfish–summary on regulated marine biotoxins. EFSA J 1306:1–23Google Scholar
- Oshima Y (1995) Postcolumnderivatization liquid chromatographic method for paralytic shellfish toxins. J AOAC Int 78:528–532Google Scholar
- Vale P (2014) Saxitoxin and analogs: ecobiology, origin, chemistry and detection. In: Botana LM (ed) Seafood and freshwater toxins. Pharmacology, physiology and detection, 3rd edn. CRC Press, Boca RatonGoogle Scholar