Abstract: A cell bioassay is provided for determining the presence in a fluid sample of a sodium channel-activating toxin wherein (a) a fluid sample is incubated in the presence of a culture of cells which express voltage-gated sodium channels and which are responsive in a dose-dependent manner to sodium channel-activating toxins and a medium comprising an agent which causes persistent activation of the voltage-gated sodium channel; (b) the culture is incubated with a medium comprising an indicator which is acted upon by living cells to generate a discernable result, (c) the culture is observed for an incidence of the result, and an observation of the result is correlated with the presence of the toxin in the sample. A simplified assay where steps (a) and (b) are effected together also is provided, as is a cell bioassay for determining the sodium channel affect of a toxin in a fluid sample.

Abstract: A cell bioassay is provided for determining the presence in a fluid sample of a sodium channel-activating toxin wherein (a) a fluid sample is incubated in the presence of a culture of cells which express voltage-gated sodium channels and which are responsive in a dose-dependent manner to sodium channel-activating toxins and a medium comprising an agent which causes persistent activation of the voltage-gated sodium channel; (b) the culture is incubated with a medium comprising an indicator which is acted upon by living cells to generate a discernable result, (c) the culture is observed for an incidence of the result, and an observation of the result is correlated with the presence of the toxin in the sample. A simplified assay where steps (a) and (b) are effected together also is provided, as is a cell bioassay for determining the sodium channel affect of a toxin in a fluid sample.

Abstract: An inventive bioassay method can be used to determine the presence in a fluid sample of a toxin having sodium channel-affecting activity. The method includes the steps of incubating a plurality of cultures of cells which are responsive in a dose-dependent manner to sodium channel-affecting toxins with (i) a medium comprising a solution of ouabain and veratridine and (ii) a portion of the fluid sample, each culture being incubated with a different concentration of the fluid sample; removing the medium and fluid sample from the cultures; incubating the cultures with a medium comprising an indicator which is acted upon by living cells to form a measurable product; measuring the amounts of product formed during the preceding step; and relating the amounts of product measured to a standard calibration curve to determine the presence of the toxin in the sample. The method is readily embodied in kit form and is amenable to automation.