Munro L J, Kokkinidis L
Department of Psychology, University of Saskatchewan, Saskatoon, Canada.
Brain Res. 1997 Jan 23;746(1-2):231-8. doi: 10.1016/s0006-8993(96)01225-5.
Dopamine (DA) D2 and gamma-aminobutyric acid (GABA)A somatodendritic receptors tonically inhibit mesolimbic projection neurons in the A10 DA cell grouping of the ventral tegmentum. In the present study we determined the contribution of the ventral tegmental area (VTA) to the expression of a classically conditioned fear-induced increase in the acoustic startle reflex. Saline applied to VTA neurons did not modify the capacity of a light previously associated with footshock to potentiate acoustic startle amplitudes; conversely, bilateral administration of the DA D2/3 agonist quinpirole or the GABAA receptor agonist muscimol into the ventral tegmentum blocked fear-potentiated startle without altering baseline acoustic startle responding. It was suggested that DA VTA neurons regulate the excitatory aspects of fear expression by gating levels of aversive emotional arousal within the amygdala-based fear system.
多巴胺（DA）D2受体和γ-氨基丁酸（GABA）A树突-体细胞受体持续性抑制腹侧被盖区A10多巴胺能细胞群中的中脑边缘投射神经元。在本研究中，我们确定了腹侧被盖区（VTA）对经典条件恐惧诱导的听觉惊吓反射增强表达的作用。向VTA神经元注射生理盐水，不会改变先前与足部电击相关的光增强听觉惊吓幅度的能力；相反，向腹侧被盖区双侧注射DA D2/3激动剂喹吡罗或GABAA受体激动剂蝇蕈醇，可阻断恐惧增强的惊吓反应，而不改变基线听觉惊吓反应。研究表明，VTA多巴胺能神经元通过调节杏仁核恐惧系统内厌恶情绪唤醒水平，来调控恐惧表达的兴奋性方面。
