Hypofunction of the serotonergic (5-HT) system has close relationship with the symptoms in major depressive disorders (MDD), however, the underlying neural circuitry mechanisms are not fully understood. Lateral habenula (LHb) plays a crucial role in aversive behaviors and is activated in conditions of depression. It has been reported that 5-HT inhibits the excitability of LHb neurons, leading to the hypothesis that decreased transmission of 5-HT would elevate the activity of LHb and therefore mediates depressive symptoms. Using retrograde tract tracing with cholera toxin subunit B, we find that dorsal raphe nucleus (DRN) sends primary 5-HT projection to the LHb. In vitro slice patch-clamp recording reveals that opto-stimulation of DRN inputs to the LHb suppresses the frequency of miniature excitatory postsynaptic current, while increases paired pulse ratio in LHb neurons, indicating 5-HT projection presynaptically suppresses the excitability of LHb neurons. In chronic unpredictable mild stress (CUMS) rat model of depression, optogenetic stimulation of DRN-LHb projection alleviates the depressive symptoms in CUMS models. Meanwhile, opto-inhibition of this circuit results in elevated c-fos expression in LHb and induces depression-like behaviors. This study demonstrates that the 5-HT projection from DRN to LHb suppresses the excitability of LHb neurons, and hypofunction of 5-HT transmission induces depressive behavior via the activation of LHb. Our results reveal the functional connectivity of DRN-LHb circuit and its antidepressant action, which may provide a novel target for the treatment of depression.
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http://dx.doi.org/10.1007/s00429-018-1623-3 | DOI Listing |
J Comp Neurol
January 2025
Graduate Program in Molecular and Systems Pharmacology, Emory University, Atlanta, Georgia, USA.
Glutamate delta receptor 1 (GluD1) is a unique synaptogenic molecule expressed at excitatory and inhibitory synapses. The lateral habenula (LHb), a subcortical structure that regulates negative reward prediction error and major monoaminergic systems, is enriched in GluD1. LHb dysfunction has been implicated in psychiatric disorders such as depression and schizophrenia, both of which are associated with GRID1, the gene that encodes GluD1.
View Article and Find Full Text PDFNat Neurosci
January 2025
Brain Research Institute, University of Zurich, Zurich, Switzerland.
Appropriate risk evaluation is essential for survival in complex, uncertain environments. Confronted with choosing between certain (safe) and uncertain (risky) options, animals show strong preference for either option consistently across extended time periods. How such risk preference is encoded in the brain remains elusive.
View Article and Find Full Text PDFFront Cell Neurosci
December 2024
Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, Friedman Brain Institute, New York, NY, United States.
Introduction: Diabetes is a metabolic disorder of glucose homeostasis that is a significant risk factor for neurodegenerative diseases, such as Alzheimer's disease, as well as mood disorders, which often precede neurodegenerative conditions. We examined the medial habenulainterpeduncular nucleus (MHb-IPN), as this circuit plays crucial roles in mood regulation, has been linked to the development of diabetes after smoking, and is rich in cholinergic neurons, which are affected in other brain areas in Alzheimer's disease.
Methods: This study aimed to investigate the impact of streptozotocin (STZ)-induced hyperglycemia, a type 1 diabetes model, on mitochondrial and lipid homeostasis in 4% paraformaldehyde-fixed sections from the MHb and IPN of C57BL/6 J male mice, using a recently developed automated pipeline for mitochondrial analysis in confocal images.
Ecotoxicol Environ Saf
January 2025
Department of Preventive Medicine, School of Public Health, Fujian Medical University, Fuzhou, China; The Key Laboratory of Environment and Health, School of Public Health, Fujian Medical University, Fuzhou, China; Fujian Provincial Key Laboratory of Environmental Factors and Cancer, School of Public Health, Fujian Medical University, Fuzhou, China. Electronic address:
The threat posed by light pollution to human health is increasing remarkably. As demand for high-efficiency and bright lighting increases, so does the blue light content from artificial sources. Although animal studies suggested blue light induced depression-like behaviors, human evidence remained limited, and the mechanisms by which blue light affects depression remained elusive.
View Article and Find Full Text PDFJ Zhejiang Univ Sci B
April 2024
Department of Neurology and International Institutes of Medicine, the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu 322000, China.
Stress has been considered as a major risk factor for depressive disorders, triggering depression onset via inducing persistent dysfunctions in specialized brain regions and neural circuits. Among various regions across the brain, the lateral habenula (LHb) serves as a critical hub for processing aversive information during the dynamic process of stress accumulation, thus having been implicated in the pathogenesis of depression. LHb neurons integrate aversive valence conveyed by distinct upstream inputs, many of which selectively innervate the medial part (LHbM) or lateral part (LHbL) of LHb.
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