Daytime spikes in dopaminergic activity drive rapid mood-cycling in mice.

Journal Article

Disruptions in circadian rhythms and dopaminergic activity are involved in the pathophysiology of bipolar disorder, though their interaction remains unclear. Moreover, a lack of animal models that display spontaneous cycling between mood states has hindered our mechanistic understanding of mood switching. Here, we find that mice with a mutation in the circadian Clock gene (ClockΔ19) exhibit rapid mood-cycling, with a profound manic-like phenotype emerging during the day following a period of euthymia at night. Mood-cycling coincides with abnormal daytime spikes in ventral tegmental area (VTA) dopaminergic activity, tyrosine hydroxylase (TH) levels and dopamine synthesis. To determine the significance of daytime increases in VTA dopamine activity to manic behaviors, we developed a novel optogenetic stimulation paradigm that produces a sustained increase in dopamine neuronal activity and find that this induces a manic-like behavioral state. Time-dependent dampening of TH activity during the day reverses manic-related behaviors in ClockΔ19 mice. Finally, we show that CLOCK acts as a negative regulator of TH transcription, revealing a novel molecular mechanism underlying cyclic changes in mood-related behavior. Taken together, these studies have identified a mechanistic connection between circadian gene disruption and the precipitation of manic episodes in bipolar disorder.

Full Text

Duke Authors

Cited Authors

  • Sidor, MM; Spencer, SM; Dzirasa, K; Parekh, PK; Tye, KM; Warden, MR; Arey, RN; Enwright, JF; Jacobsen, JPR; Kumar, S; Remillard, EM; Caron, MG; Deisseroth, K; McClung, CA

Published Date

  • November 2015

Published In

Volume / Issue

  • 20 / 11

Start / End Page

  • 1406 - 1419

PubMed ID

  • 25560763

Electronic International Standard Serial Number (EISSN)

  • 1476-5578

International Standard Serial Number (ISSN)

  • 1359-4184

Digital Object Identifier (DOI)

  • 10.1038/mp.2014.167

Language

  • eng