Effects of acidosis on the post-hypoxic recovery of synaptic transmission in gerbil hippocampal slices.

We investigated the effects of acidosis on the hypoxic neuronal damage using gerbil hippocampal slices. Acidosis has delayed the onset of harmful hypoxic depolarization, resulting in a decrease in the total hypoxic period and the hypoxic depolarization. This effect has been considered to be protective. However, the synaptic recovery after reoxygenation was attenuated when acidosis (pH: 6.2-6.9) was sustained. Conversely, the synaptic recovery was potentiated when the acidosis was restored to the physiological milieu during the reoxygenation period. These results suggest that acidosis plays a protective effect against the hypoxic neuronal damage only when rapid appreciable pH recovery is achieved during reoxygenation.