Departments of Neuroscience, Psychiatry and Psychology, University of Pittsburgh, PA 15260, USA.
Int J Neuropsychopharmacol. 2013 Oct;16(9):2013-25. doi: 10.1017/S1461145713000618. Epub 2013 Jun 10.
The basolateral amygdala (BLA) and ventral subiculum (vSub) of the hippocampus convey emotion and context information, respectively, to the nucleus accumbens (NAc). Using in vivo extracellular recordings from NAc neurons, we examined how acute and repeated restraint stress alters the plasticity of the vSub and BLA afferent pathways. High-frequency (HFS) and low-frequency (LFS) stimulation was applied to the vSub to assess the impact on NAc responses to vSub and BLA inputs. In addition, iontophoretic application of the dopamine D2-antagonist sulpiride was used to explore the role of dopamine in the NAc in mediating the effects of stress on plasticity. Acute and repeated restraint caused disparate effects on BLA- and vSub-evoked responses in the NAc. Following repeated restraint, but not after acute restraint, HFS of the vSub failed to potentiate the vSub–NAc pathway while instead promoting a long-lasting reduction of the BLA–NAc pathway and these effects were independent of D2-receptor activity. In contrast, LFS to the vSub pathway after acute restraint resulted in potentiation in the vSub–NAc pathway while BLA-evoked responses were unchanged. When sulpiride was applied prior to LFS of the vSub after acute stress, there was a pronounced decrease in vSub-evoked responses similar to control animals. This work provides new insight into the impact of acute and repeated stress on the integration of context and emotion inputs in the NAc. These data support a model of stress whereby the hippocampus is inappropriately activated and dominates the information processing within this circuit via a dopaminergic mechanism after acute bouts of stress.
外侧杏仁核 (BLA) 和海马腹侧下托 (vSub) 分别将情绪和情境信息传递到伏隔核 (NAc)。通过对 NAc 神经元进行活体细胞外记录，我们研究了急性和重复束缚应激如何改变 vSub 和 BLA 传入通路的可塑性。对 vSub 进行高频 (HFS) 和低频 (LFS) 刺激，以评估其对 NAc 对 vSub 和 BLA 输入反应的影响。此外，还使用多巴胺 D2 拮抗剂硫必利的离子电泳应用来探索多巴胺在 NAc 中在介导应激对可塑性的影响中的作用。急性和重复束缚对 NAc 中 BLA 和 vSub 诱发反应产生了不同的影响。在重复束缚后，但不是在急性束缚后，vSub 的 HFS 未能增强 vSub-NAc 通路，反而促进了 BLA-NAc 通路的持久减弱，并且这些效应与 D2 受体活性无关。相比之下，急性束缚后对 vSub 通路进行 LFS 导致 vSub-NAc 通路的增强，而 BLA 诱发的反应保持不变。当在急性应激后 LFS 之前将硫必利应用于 vSub 时，vSub 诱发的反应明显减少，类似于对照动物。这项工作提供了关于急性和重复应激对 NAc 中情境和情绪输入整合的影响的新见解。这些数据支持了一种应激模型，即在急性应激发作后，通过多巴胺能机制，海马体被不恰当地激活，并主导该回路中的信息处理。
