Quantitation of paralytic shellfish toxins using mouse brain synaptoneurosomes

Area of Science:

• Neuroscience
• Analytical Chemistry
• Marine Biology

Background:

• Saxitoxin (STX) and its analogs are potent neurotoxins found in marine organisms.
• Accurate quantification of these toxins is crucial for public health and environmental monitoring.
• Existing methods may have limitations in scope or application.

Purpose of the Study:

• To further evaluate a mouse brain synaptoneurosomal membrane potential assay for saxitoxin and related bioactive quantification.
• To assess the assay's utility in diverse sample matrices, including shellfish and zooplankton.
• To explore potential alternative reagents for the assay.

Main Methods:

• Preparation of synaptoneurosomes from mouse brain.
• Application of a membrane potential assay to quantify saxitoxin in mussel extracts.
• Testing the assay's capability with zooplankton samples.
• Comparison with [3H] saxitoxin receptor binding technique and evaluation of veratrine as a substitute reagent.

Main Results:

• The synaptoneurosomal assay accurately quantitated saxitoxin in mussel extracts, correlating well with spiked concentrations (r2 = 0.995).
• The assay detected saxitoxin-like bioactives in zooplankton samples, with results consistent with receptor binding assays.
• Veratrine demonstrated potential as a substitute for veratridine in the assay.

Conclusions:

• The mouse brain synaptoneurosomal membrane potential assay is highly capable for quantifying saxitoxin-like activity in shellfish.
• The assay is also applicable to zooplankton samples, expanding its utility in environmental monitoring.
• This method offers a reliable tool for assessing marine toxin contamination.