Neuroblastoma cell culture assay shows that Carcinoscorpius rotundicauda haemolymph neutralizes tetrodotoxin.

Veratridine facilitates the influx of Na+ into Neuro-2A cells and this process is exacerbated by the presence of a Na+/K(+)-ATPase inhibitor, ouabain, leading to a reduction in cell viability. However, tetrodotoxin neutralizes the cytotoxic effects of veratridine, hence sustaining the viability of Neuro-2A cells. This neutralizing ability was negated when TTX was first reacted with cell-free haemolymph of Carcinoscorpius rotundicauda, resulting in reduced cell viability. These results therefore indicate a bona fide effect of the cell-free haemolymph against tetrodotoxin as demonstrated by in vitro cell culture technique.