Glutamate-mediated primary somatosensory cortex excitability correlated with ceruloplasmin in healthy subjects

Objective: To investigate the biological processes linked to metal homeostasis which underlie glutamate-mediated neurotrasmission of the primary somatosensory cortex, as marked by the neuronal pool generating the earliest component (M20) of somatosensory field evoked (SEF) by right median nerve stimulation at wrist. Method: Thirty-four healthy right-handed subjects (51±22 years) underwent a magnetoencephalography (MEG) examination. A source reconstruction algorithm was applied to assess the amount of synchronously activated neurons subtending the M20 and the following SEF component (M30), which is generated by two independent contributions of gabaergic and glutamatergic transmission. Serum copper, ceruloplasmin, nonceruloplasmin- bound copper ('free'), iron, transferrin and zinc levels were evaluated. Results: Total copper and ceruloplasmin negatively correlated with the M20 ECD strength. A transferrin M20 ECD strength correlation only approached significance. Conclusion: This pilot study showed that copper homeostasis, rather than iron or zinc status seems to be involved in the physiological activities of glutamate-mediated neurotransmission of the primary somatosensory cortex.