Illustrating its cell signaling mechanism, PQQ protects neurons by modifying a key receptor site within our brain's neurotransmitter system.28,29 This inhibits excitotoxicity, a response to long-term over-stimulation of neurons that is associated with many neurodegenerative diseases and seizures.30-32 PQQ was shown to block neurotoxicity induced by other toxins, including mercury, a factor suspect