Center for Neuron and Disease, Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an 710049, China.
Zhuomin Institute of Brain Research, Qingdao International Academician Park, Qingdao 266000, China.
J Neurosci. 2024 Aug 28;44(35):e0028242024. doi: 10.1523/JNEUROSCI.0028-24.2024.
The anterior cingulate cortex (ACC) is a key cortical region for pain perception and emotion. Different forms of synaptic plasticity, including long-term potentiation (LTP) and long-term depression (LTD), have been reported in the ACC. Synaptic tagging of LTP plays an important role in hippocampus-related associative memory. In this study, we demonstrate that synaptic tagging of LTD is detected in the ACC of adult male and female mice. This form of tagged LTD requires the activation of metabotropic glutamate receptor subtype 1 (mGluR1). The induction of tagged LTD is time-related with the strongest tagged LTD appearing when the interval between two independent stimuli is 30 min. Inhibitors of mGluR1 blocked the induction of tagged LTD; however, blocking N-methyl-d-aspartate receptors did not affect the induction of tagged LTD. Nimodipine, an inhibitor of L-type voltage-gated calcium channels, also blocked tagged LTD. In an animal model of amputation, we found that tagged LTD was either reduced or completely blocked. Together with our previous report of tagged LTP in the ACC, this study strongly suggests that excitatory synapses in the adult ACC are highly plastic. The biphasic tagging of synaptic transmission provides a new form of heterosynaptic plasticity in the ACC which has functional and pathophysiological significance in phantom pain.
扣带前皮质（ACC）是疼痛感知和情绪的关键皮质区域。在 ACC 中已经报道了不同形式的突触可塑性，包括长时程增强（LTP）和长时程抑制（LTD）。LTP 的突触标记在与海马体相关的联想记忆中起着重要作用。在这项研究中，我们证明了在成年雄性和雌性小鼠的 ACC 中检测到 LTD 的突触标记。这种形式的标记 LTD 需要代谢型谷氨酸受体亚型 1（mGluR1）的激活。标记 LTD 的诱导与时间有关，当两个独立刺激之间的间隔为 30 分钟时，出现最强的标记 LTD。mGluR1 的抑制剂阻断了标记 LTD 的诱导；然而，阻断 N-甲基-D-天冬氨酸受体不会影响标记 LTD 的诱导。L 型电压门控钙通道的抑制剂尼莫地平也阻断了标记 LTD。在截肢动物模型中，我们发现标记 LTD 要么减少，要么完全阻断。结合我们之前在 ACC 中报告的标记 LTP，这项研究强烈表明成年 ACC 中的兴奋性突触具有高度可塑性。突触传递的双相标记为 ACC 中的异突触可塑性提供了一种新形式，它在幻肢痛中具有功能和病理生理学意义。
