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Dopamine attenuates evoked inhibitory synaptic currents in central amygdala neurons

Authors

  • Jennifer C. Naylor,

    1. Department of Psychiatry, Duke University Medical Center, Durham, NC, USA
    2. Durham Department of Veteran’s Affairs Medical Center, Neurology Research, Durham, NC, USA
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  • Qiang Li,

    1. Department of Psychiatry, Duke University Medical Center, Durham, NC, USA
    2. Durham Department of Veteran’s Affairs Medical Center, Neurology Research, Durham, NC, USA
    3. VISN 6 Mental Illness Research, Education and Clinical Center, Seattle, WA, USA
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  • Maeng-hee Kang-Park,

    1. Department of Psychiatry, Duke University Medical Center, Durham, NC, USA
    2. Durham Department of Veteran’s Affairs Medical Center, Neurology Research, Durham, NC, USA
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  • Wilkie A. Wilson,

    1. Durham Department of Veteran’s Affairs Medical Center, Neurology Research, Durham, NC, USA
    2. Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC, USA
    3. VISN 6 Mental Illness Research, Education and Clinical Center, Seattle, WA, USA
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  • Cynthia Kuhn,

    1. Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC, USA
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  • Scott D. Moore

    1. Department of Psychiatry, Duke University Medical Center, Durham, NC, USA
    2. Durham Department of Veteran’s Affairs Medical Center, Neurology Research, Durham, NC, USA
    3. VISN 6 Mental Illness Research, Education and Clinical Center, Seattle, WA, USA
    4. Durham Department of Veteran’s Affairs Medical Center, Department of Psychiatry, Durham, NC, USA
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Scott D. Moore, MD, PhD, 1Department of Psychiatry, as above.
E-mail: sdmoore@duke.edu

Abstract

The central nucleus of the amygdala (CeA) plays a critical role in regulating the behavioral, autonomic and endocrine response to stress. Dopamine (DA) participates in mediating the stress response and DA release is enhanced in the CeA during stressful events. However, the electrophysiological effects of DA on CeA neurons have not yet been characterized. Therefore, the purpose of this study was to identify and characterize the effect of DA application on electrophysiological responses of CeA neurons in coronal brain sections of male Sprague–Dawley rats. We used whole-cell patch-clamp electrophysiological techniques to record evoked synaptic responses and to determine basic membrane properties of CeA neurons both before and after DA superfusion. DA (20–250 μm) did not significantly alter membrane conductance over the voltage range tested. However, DA significantly reduced the peak amplitude of evoked inhibitory synaptic currents in CeA neurons. Pretreatment with the D2 receptor antagonist eticlopride failed to significantly block the inhibitory effects of DA. In contrast, pretreatment with the D1 receptor antagonist SCH-23390 significantly reduced the effects of DA on evoked inhibitory neurotransmission in these neurons. Moreover, bath superfusion of the specific D1 receptor agonist SKF-39393, but not the D2 receptor agonist quinpirole, significantly reduced peak amplitude of evoked inhibitory synaptic events. DA reduced the frequency of miniature IPSCs without altering the amplitude, while having no effect on the amplitude of IPSCs elicited by pressure application of GABA. These results suggest that DA may modulate inhibitory synaptic transmission in CeA through D1 receptor activation primarily by a presynaptic mechanism.

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