Neuron-astrocyte Coupling in Lateral Habenula Mediates Depressive-like Behaviors

The lateral habenular (LHb) neurons and astrocytes have been strongly implicated in depression etiology but it was not clear how the two dynamically interact during depression onset. Here, using multi-brain-region calcium photometry recording in freely-moving mice, we discover that stress induces a unique, bimodal neuronal response and a most rapid astrocytic response in the LHb. LHb astrocytic calcium requires the α _1A -adrenergic receptor, and depends on a recurrent neural network between the LHb and locus coeruleus (LC). Through the gliotransmitter glutamate and ATP/Adenosine, LHb astrocytes mediate the second-wave activation of local LHb neurons as well as release of norepinephrine (NE). Activation or inhibition LHb astrocytic calcium signaling facilitates or prevents stress-induced depressive-like behaviors respectively. These results identify a stress-induced positive feedback loop in the LHb-LC axis, with astrocytes being a critical signaling relay. The identification of this prominent neuron-glia interaction may shed light on stress management and depression prevention.