Metal toxicity at the synapse: presynaptic, postsynaptic, and long-term effects.

Area of Science:

• Neuroscience
• Toxicology
• Cell Biology

Background:

• Metal neurotoxicity poses a significant global health challenge.
• Understanding metal interactions with neuronal processes is crucial for public health.

Purpose of the Study:

• To review the evidence on how metals affect synaptic transmission and plasticity.
• To elucidate the mechanisms of metal-induced neurotoxicity at the synaptic level.

Main Methods:

• Literature review of studies investigating metal ion effects on neuronal function.
• Analysis of research on presynaptic and postsynaptic mechanisms affected by metals.
• Examination of metals' impact on neurotransmitter receptors and intracellular signaling.

Main Results:

• Metals modulate neurotransmitter release by interacting with synaptic vesicles and ion channels.
• Specific metals (e.g., Pb(2+), Cd(2+), Hg(+)) alter neurotransmitter metabolism and intracellular pathways.
• Metals like Zn(2+), Cu(2+), and methylmercury affect key neurotransmitter receptors (NMDA, AMPA/kainate, GABA).
• Impairment of synaptic plasticity by metals (e.g., Al(3+), As(2)O(3)) involves critical molecules (CaM, PKC, NOS) and transcription.

Conclusions:

• Metals exert diverse neurotoxic effects by interfering with synaptic transmission and plasticity.
• The specific impact of metals depends on the metal type, concentration, and neuronal context.
• Metal-induced disruption of synaptic function represents a critical mechanism of neurotoxicity.