The action of hydrogen peroxide on paired pulse and long-term potentiation in the hippocampus

Abstract

The action of a reactive oxygen intermediate, that is, hydrogen peroxide (H₂O₂) on modulation of synaptic transmission was examined in the hippocampal brain slice preparation. Microinjection of H₂O₂ into the apical dendritic region of the CA1 pyramidal cells produced no change in either the pattern or amplitude of paired pulse facilitation compared to saline injection (control). Long term potentiation (LTP), induced by high frequency stimulation of homosynaptic inputs, however, was blocked by microinjection of H₂O₂ into the dendritic tree. LTP was seen in only 2 out of 10 slices investigated when treated with H₂O₂ while LTP was seen in 4 out 5 slices when saline injected. The results suggest that a reactive oxygen intermediate can selectively modify synaptic mechanisms in the hippocampus.