Figure 8.
Activity-dependent channel-mediated lactate release by astrocytes. Resting astrocytes maintain a standing reservoir of cytosolic lactate, the result of a dynamic balance between glycolytic production and MCT-mediated lactate export. Active neurons release K+, which depolarizes the astrocytic plasma membrane (ΔVm) and activates the lactate-permeable channel, resulting in lactate release, leading to higher [lactate]o and further lactate release through a positive feedback. Neurons may sense lactate through HCA1 (Bozzo et al., 2013; Lauritzen et al., 2013) and other surface lactate receptors (Tang et al., 2014), or after internalization of lactate via MCTs.