Domoic acid is a potent amino acid neuroexcitant that acts preferentially upon a sub-class of ionotropic glutamate receptors found in nervous tissue, particularly the brain. These glutamate receptors ligand gated ion channels, which respond to L-glutamate by opening and allowing the passage of cations. This action triggers many intracellular cascades either directly by their introduction of cations or indirectly by the second messengers produced by these cascades such as cyclic AMP, or reactive oxygen species.
Domoic acid structure is very similar to glutamic (and Kainic) acid and nerve cells do not recognize the difference. Glutamic acid is a neurotransmitter that allows the flow of Calcium ions into the cell. Excess glutamate in the system acts as a exitotoxin, a toxin that causes over excitement of the cells. During poisoning by Domoic acid or Glutamic acid, all the Calcium ions begin to enter the cell at once, causing it to overfire, swell and eventually burst.
Induction of neuronal imbalance can cause the brain to malfunction and may lead to lesions in the brain that can cause permanent injury. (resulting in permanent neurological disease) (2)