Invitro study of domoic acid uptake by digestive gland tissue of blue mussel (Mytilus-edulis-L)

Domoic acid is a neurotoxic amino acid responsible for an outbreak of human food poisoning in late 1987 following consumption of contaminated blue mussels (Mytilus edulis L.) from eastern Prince Edward Island, Canada. In vitro techniques were used to examine the uptake of domoic acid by digestive gland tissue of the blue mussel. Uptake of domoic acid over different periods of time by digestive gland tissue was compared with that of structurally related amino acids, glutamic acid and kainic acid. Domoic acid uptake was observed to be a function of time and concentration. Uptake of glutamic acid, which is a physiological amino acid, was greater than that of domoic acid. Kainic acid, a non-protein, rare amino acid, was least absorbed. In a series of experiments to determine the inhibitory actions of chemically similar and dissimilar amino acids, kainic acid, glutamic acid and proline inhibited the uptake of domoic acid by 42, 38 and 34%, respectively, indicating competition for the same carrier site. Glycine, which showed least inhibition is likely to have a separate pathway. A marginal enhancing effect of ATP and slight inhibitory effects of metabolic inhibitors (NaCN and maleic acid) suggested that uptake of domoic acid by digestive gland tissue is not totally an energy-dependent process.