1. Behavioral Engagement With Playable Objects Resolves Stress-Induced Adaptive Changes by Reshaping the Reward System
- Author
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Jin Young Park, Eun-Hwa Lee, Ji-Seon Seo, Kyoung-Shim Kim, In-Sun Baek, Pyung Lim Han, and Hye-Jin Kwon
- Subjects
Dopamine ,Ventral Tegmental Area ,Neuropeptide ,Antidepressive Agents ,Nucleus Accumbens ,Ventral pallidum ,Mice ,Reward system ,Reward ,Downregulation and upregulation ,Dopamine receptor ,Dopamine receptor D2 ,medicine ,Animals ,Pituitary Adenylate Cyclase-Activating Polypeptide ,Chronic stress ,Psychology ,Neuroscience ,Biological Psychiatry ,medicine.drug - Abstract
Background The reward system regulates motivated behavior, and repeated practice of specific motivated behavior might conversely modify the reward system. However, the detailed mechanisms by which they reciprocally regulate each other are not clearly understood. Methods Mice subjected to chronic restraint stress show long-lasting depressive behavior, which is rescued by continual engagement with playable objects. A series of molecular, pharmacological, genetic, and behavioral analyses, combined with microarray, liquid chromatography, and chemogenetic tools are used to investigate the neural mechanisms of anti-depressive effects of playable objects. Results Here we show that repeated restraint induces dopamine surges into the nucleus accumbens-lateral shell (NAc-lSh), which cause upregulation of the neuropeptide PACAP in the NAc-lSh. As repeated stress is continued, the dopamine surge by stressors is adaptively suppressed without restoring the PACAP upregulation, and the resulting enhanced PACAP inputs from NAc-lSh neurons to the ventral pallidum (VP) facilitate depressive-like behaviors. Continual engagement with playable objects in mice subjected to chronic stress remediates the reduced dopamine response to new stressors, enhanced PACAP upregulation, and depressive-like behaviors. Overactivation of D1 dopamine receptors over the action of D2 receptors in the NAc-lSh promotes depressive-like behaviors. Conversely, inhibition of D1 receptors or PACAP upregulation in the NAc-lSh confers resilience to chronic stress-induced depressive-like behaviors. Histochemical and chemogenetic analyses reveal that engagement with playable objects produces anti-depressive effects by reshaping the ventral tegmental area-to-NAc-lSh and NAc-lSh-to-VP circuits. Conclusions These results suggest that behavioral engagement with playable objects remediates depressive-like behaviors by resolving stress-induced maladaptive changes in the reward system.
- Published
- 2022