Yang X D, Korn H, Faber D S
Department of Physiology, School of Medicine, State University of New York, Buffalo 14214.
Nature. 1990 Dec 6;348(6301):542-5. doi: 10.1038/348542a0.
Long-term potentiation of chemical synapses is closely related to memory and learning. Studies of this process have concentrated on chemically mediated excitatory synapses. By contrast, activity-dependent modification of gap junctions, which also widely exist in higher structures such as hippocampus and neocortex, has not been described. Here we report that at mixed synapses between sensory afferents and an identified reticulospinal neuron, the electrotonic coupling potential can be potentiated, as well as the chemically mediated excitatory postsynaptic potential, for a prolonged time period using a stimulation paradigm like that which produces long-term potentiation in hippocampus. The effect on coupling is due to an increase in gap-junctional conductance. Our data indicate that the potentiation of both synaptic components requires an increase in intracellular calcium, involves activation of NMDA (N-methyl-D-aspartate) receptors, and is specific to the tetanized pathway.
化学突触的长期增强与记忆和学习密切相关。对这一过程的研究主要集中在化学介导的兴奋性突触上。相比之下，缝隙连接的活动依赖性修饰在海马体和新皮层等高级结构中也广泛存在，但尚未见相关描述。在此，我们报告，在感觉传入神经与一个已鉴定的网状脊髓神经元之间的混合突触处，使用类似于在海马体中产生长期增强的刺激模式，电紧张性耦合电位以及化学介导的兴奋性突触后电位可在较长时间段内得到增强。对耦合的影响是由于缝隙连接电导增加所致。我们的数据表明，两种突触成分的增强都需要细胞内钙增加，涉及N-甲基-D-天冬氨酸（NMDA）受体的激活，并且对强直刺激的通路具有特异性。
