Oxidative stress and brain glutamate-mediated excitability in depressed patients

Introduction Several neuropsychiatric pathologies have been recently linked to oxidative stress. Objectives In this study, we investigated the relationship between depression, markers of oxidative stress and neurotransmission, as expressed by sensory cortex excitability. Methods Serum levels of oxidative stress markers and somatosensory magnetic fields, evokedby external galvanic stimulation, were measured in 13 depressed patients and 13 controls. Results Depressives had higher levels of total and free copper than controls and lower levels oftransferrin. They also showed lower sensory cortex excitability, which correlated with copperlevels in controls, but not in patients. Transferrin correlated with sensory cortex excitability inboth patients and controls, although in opposite ways. Copper level results associated with thepatients' clinical status. Conclusions Pro-oxidant agents appear to affect neuronal excitability and clinical state ofdepressed patients, as free copper excess alters their cortical glutamatergic neurotransmission.