Neurosteroid dehydroepiandrosterone sulfate enhances spontaneous glutamate release in rat prelimbic cortex through activation of dopamine D1 and sigma-1 receptor

This paper studied the effect of neurosteroid dehydroepiandrosterone sulfate on spontaneous glutamate release in the prelimbic cortex by using electrophysiological and biochemical methods combined with a pharmacological approach and made some comparisons with those in the hippocampus. The results showed that dehydroepiandrosterone sulfate increased the frequency of miniature excitatory postsynaptic currents in the prelimbic cortex and hippocampus; sigma-l receptor antagonist partially blocked the effect of dehydroepiandrosterone sulfate in the prelimbic cortex, but completely blocked it in the hippocampus; D I receptor antagonist, adenylyl cyclase inhibitor and protein kinase A inhibitor completely blocked the effect of dehydroepiandrosterone sulfate in the prelimbic cortex; dehydroepiandrosterone sulfate increased the activity of protein kinase A in the prelimbic cortex and hippocampus; the effect of dehydroepiandrosterone sulfate on protein kinase A was completely blocked by sigma-1 receptor antagonist in the hippocampus, but was partially blocked in the prelimbic cortex; interestingly, here again, the effect of dehydroepiandrosterone sulfate on protein kinase A was completely blocked by D I receptor antagonist in the prelimbic cortex. These results suggest that dehydroepiandrosterone sulfate promotes presynaptic glutamate release in the prelimbic cortex via activation of D1 and sigma-1 receptors. (c) 2006 Elsevier Ltd. All rights reserved.