期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2021
卷号：118
期号：37
DOI：10.1073/pnas.2102635118
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Significance
Learning depends on synaptic plasticity. The signaling mechanisms that control induction of plasticity determine the learning rules at the specific synapse involved. Moreover, the relationship between the activity patterns of synaptic inputs and the type, direction, and level of plasticity induced may evolve during development. Here, we establish a key link between receptor activation presynaptic to cerebellar Purkinje cells, downstream signaling mechanisms, and the ability of adult animals to learn a cerebellar motor task.
Long-term synaptic plasticity is believed to be the cellular substrate of learning and memory. Synaptic plasticity rules are defined by the specific complement of receptors at the synapse and the associated downstream signaling mechanisms. In young rodents, at the cerebellar synapse between granule cells (GC) and Purkinje cells (PC), bidirectional plasticity is shaped by the balance between transcellular nitric oxide (NO) driven by presynaptic
N-methyl-D-aspartate receptor (NMDAR) activation and postsynaptic calcium dynamics. However, the role and the location of NMDAR activation in these pathways is still debated in mature animals. Here, we show in adult rodents that NMDARs are present and functional in presynaptic terminals where their activation triggers NO signaling. In addition, we find that selective genetic deletion of presynaptic, but not postsynaptic, NMDARs prevents synaptic plasticity at parallel fiber-PC (PF-PC) synapses. Consistent with this finding, the selective deletion of GC NMDARs affects adaptation of the vestibulo-ocular reflex. Thus, NMDARs presynaptic to PCs are required for bidirectional synaptic plasticity and cerebellar motor learning.
