Review Article
Metal Toxicity at the Synapse: Presynaptic, Postsynaptic, and Long-Term Effects
Table 2
Effects of metals on presynaptic signaling pathways (↑—activation/upregulation, ↓—inhibition/downregulation).
| Target | |
Pathways | | | | | | PKC | Adenylate cyclase | Phosphodiesterase | CaM | IP3 | Intracellular calcium |
| Al | Effect | ↓ | ↑ | | | | ↓ | | ↑ | Conc | 0–100 μM | | | | | 0–1000 microM | | 0–1000 μM | Ref | [2] | [23] | | | | [2] | | [2] |
| As | Effect | | | | | | | | ↑ | Conc | | | | | | | | 1 μM | Ref | | | | | | | | [24] |
| Cd | Effect | | | | ↓ | ↓ | | | ↑ | Conc | | | | 0.4, 0.9, 1.4 (i) μM | | | | 0.1–1 mM | Ref | | | | [25], [25], [25] | [25] | | | [26] |
| Hg | Effect | | | | ↓ | ↓ | | | | Conc | | | | 0.8, 0.5, 0.9 (i) μM | | | | | Ref | | | | [25], [25], [25] | [25] | | | |
| Ni | Effect | ↓ | | | | | | | | Conc | 30 μM | | | | | | | | Ref | [27] | | | | | | | |
| Pb | Effect | | | NC | ↓ | ↓ | | | | Conc | | | 1500–10000 ppm | 2.5, 8.6,1.9, 8.0 (i)μM | | | | | Ref | | | [25] | [28], [25], [25], [25] | [25] | | | |
| Pt | Effect | | | | | | | ↑ | ↑ | Conc | | | | | | | 1 nM–10 μM | 1 nM–10 μM | Ref | | | | | | | [29] | [29] |
| Zn | Effect | | | | ↓ | | | | | Conc | | | | 1-2 μM | | | | | Ref | | | | [30] | | | | |
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(i)The three different concentrations indicate actions in different areas of the brain—cerebrum, cerebellum, and brainstem.
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