Midbrain Dopamine Controls Anxiety-like Behavior by Engaging Unique Interpeduncular Nucleus Microcircuitry
Department of Neurobiology, Brudnick Neuropsychiatric Research Institute; Graduate School of Biomedical Sciences, Program in Neuroscience; Gardner Lab; Tapper Lab
Neuroscience and Neurobiology
BACKGROUND: Dopamine (DA) is hypothesized to modulate anxiety-like behavior, although the precise role of DA in anxiety behaviors and the complete anxiety network in the brain have yet to be elucidated. Recent data indicate that dopaminergic projections from the ventral tegmental area (VTA) innervate the interpeduncular nucleus (IPN), but how the IPN responds to DA and what role this circuit plays in anxiety-like behavior are unknown.
METHODS: We expressed a genetically encoded G protein-coupled receptor activation-based DA sensor in mouse midbrain to detect DA in IPN slices using fluorescence imaging combined with pharmacology. Next, we selectively inhibited or activated VTA-->IPN DAergic inputs via optogenetics during anxiety-like behavior. We used a biophysical approach to characterize DA effects on neural IPN circuits. Site-directed pharmacology was used to test if DA receptors in the IPN can regulate anxiety-like behavior.
RESULTS: DA was detected in mouse IPN slices. Silencing/activating VTA-->IPN DAergic inputs oppositely modulated anxiety-like behavior. Two neuronal populations in the ventral IPN (vIPN) responded to DA via D1 receptors (D1Rs). vIPN neurons were controlled by a small population of D1R neurons in the caudal IPN that directly respond to VTA DAergic terminal stimulation and innervate the vIPN. IPN infusion of a D1R agonist and antagonist bidirectionally controlled anxiety-like behavior.
CONCLUSIONS: VTA DA engages D1R-expressing neurons in the caudal IPN that innervate vIPN, thereby amplifying the VTA DA signal to modulate anxiety-like behavior. These data identify a DAergic circuit that mediates anxiety-like behavior through unique IPN microcircuitry.
Anxiety, Circuitry, Dopamine, Interpeduncular nucleus, Medial habenula, Ventral tegmental area
DOI of Published Version
DeGroot SR, Zhao-Shea R, Chung L, Klenowski PM, Sun F, Molas S, Gardner PD, Li Y, Tapper AR. Midbrain Dopamine Controls Anxiety-like Behavior by Engaging Unique Interpeduncular Nucleus Microcircuitry. Biol Psychiatry. 2020 Jun 30:S0006-3223(20)31707-8. doi: 10.1016/j.biopsych.2020.06.018. Epub ahead of print. PMID: 32800629. Link to article on publisher's site
DeGroot SR, Zhao-Shea R, Chung L, Klenowski PM, Sun F, Molas-Casacuberta S, Gardner PD, Li Y, Tapper AR. (2020). Midbrain Dopamine Controls Anxiety-like Behavior by Engaging Unique Interpeduncular Nucleus Microcircuitry. University of Massachusetts Medical School Faculty Publications. https://doi.org/10.1016/j.biopsych.2020.06.018. Retrieved from https://escholarship.umassmed.edu/faculty_pubs/1783