Zinc changes evoked by phenolic compounds and effect on TEA-LTP at hippocampal mossy fiber synapses

The analysis of phenolic compounds pollution on health is a topic of major concern, in particular the effects associated with cellular damages. In central nervous system zinc can be either a neuromodulator or a neurotoxin, depending on the intracellular concentration and may be implicated in various neurodegenerative diseases. This work focused on the influence of phenolic pollutants on postsynaptic zinc changes, including during chemically induced long term potentiation (LTP). The study was performed in hippocampal slices from Wistar rats at the zinc-rich mossy fiber synapses. Zinc changes were detected by means of the permeant fluorescent zinc probe Newport Green. A mixture of six phenolic pollutants caused a reversible enhancement of zinc signals, indicating that those compounds cause zinc entry into neurons. The action of the phenolic compounds was also evaluated on zinc changes associated with TEA induced LTP. It was found that the zinc signals decreased in a reversible way in the presence of TEA, as observed in control experiments. This reduction may be due to the activation of presynaptic KATP channels, suggesting that mossy fiber TEA-LTP is not significantly affected by the pollutants.