Zinc, magnesium and copper profiles in three experimental models of epilepsy

Trace metals are involved in the mechanisms of CNS excitability, including epilepsy. In this study, atomic absorption spectrophotometry was used to determine concentrations of Mg2+, Cu2+ and Zn2+ in plasma (μg/ml) and hair (μg/g) samples. Differential profiles of trace metals were detected in rats displaying three different kinds of seizures, i.e. acute audiogenic seizures (generalized tonic–clonic type GTC) and audiogenic kindling (limbic type; LS) in Wistar Audiogenic Rats (WARs) and electroshock-induced seizures (ES) in Wistar non-epileptic rats (resistant). Significantly lower Zn2+ concentrations were observed in the plasma of WARs (0.80±0.02) compared with resistants (0.89±0.03) in the basal (non-seizing) condition. After GTC, WARs showed lower Zn2+ levels (0.64±0.12) while both Mg2+ (12.56±1.51) and Cu2+ (0.81±0.14) were higher than in non-seizing WARs. After ES-induced seizures only Mg2+ changed, being higher than in the basal condition (11.78±2.25 and 8.90±0.95). In hair, basal levels of Mg2+ and Cu2+ (192.49±36.73 and 13.33±1.76) were higher whereas Zn2+ (136.53±15.67) was lower in WARs than in resistants. WARs submitted to 0, 3 and 25 stimuli presented higher Mg2+ concentrations as the number of stimuli increased. In animals receiving the same number of stimuli, Zn2+ levels were higher for animals displaying GTC (151.09±5.53) than those displaying LS (128.07±8.51). In conclusion, seizure type (limbic or generalized tonic–clonic) and number of stimuli seem to be the determinant factors for changes in Zn2+ and Mg2+ levels, respectively.