HCN2 channels in the ventral tegmental area regulate behavioral responses to chronic stress

Elife. 2018 Jan 2;7:e32420. doi: 10.7554/eLife.32420.

Abstract

Dopamine neurons in the ventral tegmental area (VTA) are powerful regulators of depression-related behavior. Dopamine neuron activity is altered in chronic stress-based models of depression, but the underlying mechanisms remain incompletely understood. Here, we show that mice subject to chronic mild unpredictable stress (CMS) exhibit anxiety- and depressive-like behavior, which was associated with decreased VTA dopamine neuron firing in vivo and ex vivo. Dopamine neuron firing is governed by voltage-gated ion channels, in particular hyperpolarization-activated cyclic nucleotide-gated (HCN) channels. Following CMS, HCN-mediated currents were decreased in nucleus accumbens-projecting VTA dopamine neurons. Furthermore, shRNA-mediated HCN2 knockdown in the VTA was sufficient to recapitulate CMS-induced depressive- and anxiety-like behavior in stress-naïve mice, whereas VTA HCN2 overexpression largely prevented CMS-induced behavioral deficits. Together, these results reveal a critical role for HCN2 in regulating VTA dopamine neuronal activity and depressive-related behaviors.

Keywords: action potential; anxiety; chronic mild stress (CMS); depression; dopamine neuron; mouse; neuroscience.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Action Potentials
  • Animals
  • Depression / physiopathology*
  • Dopaminergic Neurons / physiology*
  • Gene Expression
  • Gene Knockdown Techniques
  • Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels / genetics
  • Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels / metabolism*
  • Mice
  • Potassium Channels / genetics
  • Potassium Channels / metabolism*
  • Stress, Physiological*
  • Ventral Tegmental Area / physiology*

Substances

  • Hcn2 protein, mouse
  • Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels
  • Potassium Channels