A sex difference in mouse dopaminergic projections from the midbrain to basolateral amygdala

Biology of Sex Differences

Research

Erica R. Glasper¹  Kuan Hong Wang²  Matthew T. C. Manion³ 

[1] Department of Psychology, University of Maryland, 20742, College Park, MD, USA;Program in Neuroscience and Cognitive Science, University of Maryland, 20742, College Park, MD, USA;Department of Neuroscience and Institute for Behavioral Medicine Research, The Ohio State University, 43235, Columbus, OH, USA;Unit on Neural Circuits and Adaptive Behaviors, National Institute of Mental Health, National Institutes of Health, 20892, Bethesda, MD, USA;Department of Neuroscience, Del Monte Institute for Neuroscience, University of Rochester Medical Center, 14642, Rochester, NY, USA;Unit on Neural Circuits and Adaptive Behaviors, National Institute of Mental Health, National Institutes of Health, 20892, Bethesda, MD, USA;Department of Psychology, University of Maryland, 20742, College Park, MD, USA;Program in Neuroscience and Cognitive Science, University of Maryland, 20742, College Park, MD, USA;

关键词: Dopamine;    Basolateral amygdala;    Sex difference;    Axon projections;    Synaptic boutons;   

DOI  :  10.1186/s13293-022-00486-4

 received in 2022-07-22, accepted in 2022-12-20,  发布年份 2022

来源: Springer

【 摘 要 】

BackgroundDopaminergic circuits play important roles in the motivational control of behavior and dysfunction in dopaminergic circuits have been implicated in several psychiatric disorders, such as schizophrenia and depression. While these disorders exhibit different incidence rates in men and women, the potential sex differences in the underlying neural circuits are not well-understood. Previous anatomical tracing studies in mammalian species have revealed a prominent circuit projection connecting the dopaminergic midbrain ventral tegmental area (VTA) to the basolateral amygdala (BLA), which is involved in emotional processing and associative learning. However, whether there is any sex difference in this anatomical circuit remains unknown.MethodsTo study the potential sex differences in the VTA-to-BLA dopaminergic circuit, we injected two viral vectors encoding fluorescent reporters of axons and synaptic boutons (AAV–FLEX–tdTomato and AAV–FLEX–SynaptophysinGFP, respectively) into the VTA of a mouse transgenic driver line (tyrosine hydroxylase promoter-driven Cre, or TH-Cre), which restricts the reporter expression to dopaminergic neurons. We then used confocal fluorescent microscopy to image the distribution and density of dopaminergic axons and synaptic boutons in serial sections of both male and female mouse brain.ResultsWe found that the overall labeling intensity of VTA-to-BLA dopaminergic projections is intermediate among forebrain dopaminergic pathways, significantly higher than the projections to the prefrontal cortex, but lower than the projections to the nucleus accumbens. Within the amygdala areas, dopaminergic axons are concentrated in BLA. Although the size of BLA and the density of dopaminergic axons within BLA are similar between male and female mice, the density of dopaminergic synaptic boutons in BLA is significantly higher in male brain than female brain.ConclusionsOur results demonstrate an anatomical sex difference in mouse dopaminergic innervations from the VTA to BLA. This finding may provide a structural foundation to study neural circuit mechanisms underlying sex differences in motivational and emotional behaviors and related psychiatric dysfunctions.

【 授权许可】

CC BY   
© The Author(s) 2022

【 图 表 】

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