Striatal cholinergic and dopaminergic driven astrocyte Ca2+ activity is disrupted in Parkinsonian mice.

Brain neuromodulatory systems exert powerful effects on local neuronal circuit function and behavior. In addition to classical actions directly on neurons, growing evidence indicates that neuromodulators also recruit Ca2+-dependent astrocyte mechanisms to regulate synaptic plasticity and network function. The dorsal striatum integrates cortical and thalamic inputs under strong dopamine (DA) and acetylcholine (ACh) neuromodulatory control. To what extent the circuit and behavioral effects of striatal ACh and DA depend on astrocyte Ca2+ activity remains unclear. We show that locomotion elicits robust DA, ACh, and astrocyte Ca2+ activity in the dorsolateral striatum (DLS). DA and ACh release exhibits a negative correlation on a fast time scale but shows a positive correlation during continuous locomotion as slower astrocyte Ca2+ activity builds. Higher ACh and DA release is associated with higher astrocyte events, suggesting that both neurotransmitters drive astrocyte activity. In agreement, pharmacological blockade of muscarinic ACh or D1/D2 DA receptors decreases locomotion-evoked astrocyte Ca2+. Closed-loop optogenetic inhibition of striatal cholinergic interneurons (CINs) during locomotion reduces astrocyte Ca2+ activity, demonstrating a causal contribution of ACh release to astrocyte activity. Locomotion related ACh release was severely compromised in a mouse model of Parkinson's disease (PD), with the dual loss of DA and ACh attenuating astrocyte Ca2+ activity. Facilitating astrocyte cholinergic signaling via chemogenetics improved both calcium activity and motor deficits in our recent work. Thus, the pathophysiology of PD in part involves attenuated astrocyte Ca2+ signaling, placing these non-neuronal cells as a prime underexplored therapeutic target for PD.