Toyoda Hiroki, Zhao Ming-Gao, Zhuo Min
Department of Physiology, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada.
Eur J Neurosci. 2005 Jul;22(2):485-94. doi: 10.1111/j.1460-9568.2005.04236.x.
The anterior cingulate cortex (ACC) is thought to be important for the establishment, consolidation and retrieval of permanent memory. In many brain regions, including the hippocampus, it is suggested that long-term potentiation (LTP) and long-term depression (LTD), the cellular mechanisms for learning and memory, require the activation of glutamate N-methyl-D-aspartate receptors (NMDARs). In the hippocampus, the NR2A subunit is believed to be involved in the induction of LTP, whereas the NR2B subunit contributes to the formation of LTD. However, LTD has been less well studied in the ACC as compared with the hippocampus and little is known about the role of NMDA subtype receptors in cingulate LTD. Here we show that LTD can be induced by the combination of presynaptic stimulation with postsynaptic depolarization ('pairing training') in adult mouse ACC neurons. This form of LTD is an NMDAR- and voltage-dependent mechanism and a postsynaptic Ca2+ increase is required for the induction of LTD. Furthermore, our studies provide direct physiological evidence that both NR2A and NR2B subunits are involved in the induction of LTD in the ACC.
前扣带皮层（ACC）被认为对永久记忆的建立、巩固和提取至关重要。在包括海马体在内的许多脑区，有研究表明，作为学习和记忆的细胞机制，长时程增强（LTP）和长时程抑制（LTD）需要谷氨酸N-甲基-D-天冬氨酸受体（NMDARs）的激活。在海马体中，NR2A亚基被认为参与LTP的诱导，而NR2B亚基则有助于LTD的形成。然而，与海马体相比，ACC中对LTD的研究较少，关于NMDA亚型受体在扣带回LTD中的作用也知之甚少。在此，我们表明，在成年小鼠ACC神经元中，通过突触前刺激与突触后去极化相结合（“配对训练”）可诱导LTD。这种形式的LTD是一种依赖NMDAR和电压的机制，LTD的诱导需要突触后Ca2+增加。此外，我们的研究提供了直接的生理学证据，表明NR2A和NR2B亚基均参与ACC中LTD的诱导。
