Lactate has been viewed as an end-product of the anaerobic glucose metabolism and it is now emerging as a neuromodulator. Lactate has been implicated in memory formation and to have a protective role in a certain brain pathology such as ischemia. In addition to local brain lactate production, lactate can be transported from the blood to the brain via MCTs transporters. Lactate transport is driven by a high blood-to-brain lactate concentration gradient which is observed e.g. upon exhausting physical exercise. Moreover, an increased rate of ‘anaerobic’ glycolysis and lactate accumulation has been indicated in the brain pathology, such as epileptic seizures and hypoxic-ischemic insult. Recently, a specific lactate receptor, G-protein-coupled receptor 81 (GPR81, also: HCA1) was found in the brain. In vitro studies show that neuronal excitability can be modulated via HCA1. My goal is to understand what is the role of lactate receptor and lactate in neuronal excitability and epilepsy.