This study investigated the effect of Plantagin polyphenol on NMDA receptor binding sites using glycine, Mg2+ and Zn2+ ions. A suspension of rat brain synaptosomes was isolated by differential centrifugation. Changes [Ca2+]in concentration in the suspension medium of rat brain synaptosomes were measured using the fluorescent probe Fluo-4 AM. It was noted that synaptosomal Ca2+ transport remained virtually unchanged under the influence of plantago polyphenols in Zn2+ and Mg2+ in rat brain synaptosomal suspensions incubated with L-glutamate-Fluo-4 AM. The polyphenol Plantagin competes with glycine for binding to the glycine site of NMDA receptors, reducing the likelihood of full receptor activation even in the presence of glutamate, which leads to a limitation of Ca²⁺ influx, and therefore plays an important role in preventing excitotoxicity.

Plantagin polyphenol, NMDA receptor, synaptosome

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