The role of lactate in cerebral energy metabolism has been investigated widely. The ability of lactate as the sole energy substrate to support synaptic function has been demonstrated by different studies. In many studies, lactate has been proven to be a preferred or even an obligatory substrate over glucose for aerobic energy production during the initial stage of recovery from cerebral ischemia or hypoxia for recovery from ATP-depleted synaptic function and exogenously supplied lactate can support the early recovery of synaptic function after hypoxia.