Does astrocytic L-lactate enhance cognition through myelination?

Introduction:Astrocytes,the predominant glial cell in the brain,play a vital role in a plethora of central nervous system functions.They are the major storage site of glycogen in the central nervous system.They produce L-lactate by glycogenolysis and glycolysis which is then transported to neurons(Magistretti and Allaman,2018).Multiple evidence using diverse behavioral paradigms,such as fear conditioning,conditioned place avoidance,rat gambling task(RGT),and flavor-place paired associate(PA)learning suggest that L-lactate has a beneficial effect on various aspects of cognition(Wang et al.,2017;Akter et al.,2023b).While the molecular mechanisms underlying the cognitive benefits of L-lactate are still emerging,it is well-established that astrocytic L-lactate can be used as an energy substrate by neurons and can induce N-methyl-D-aspartate receptor-dependent plasticity-driven gene expression during cognition(Magistretti and Allaman,2018).Additionally,recent evidence has revealed more roles of L-lactate which include myelination,neuronal mitochondrial biogenesis,and antioxidant defense(Sanchez-Abarca et al.,2001;Ichihara et al.,2017;Akter et al.,2023a,b).Myelin in the central nervous system is a specialized lipid-rich membrane formed by oligodendrocytes.