Mendoza Ernesto, Galarraga Elvira, Tapia Dagoberto, Laville Antonio, Hernandez-Echeagaray Elizabeth, Bargas José
Departamento de Biofísica, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México City, México 04510.
Synapse. 2006 Dec 1;60(7):533-42. doi: 10.1002/syn.20331.
Long term synaptic plasticity has been more extensively studied in excitatory synapses, but it is also a property of inhibitory synapses. Many inhibitory synapses target hippocampal pyramidal neurons of the CA1 region. They originate from several interneuron classes that subdivide the surface area that they target on the pyramidal cell. Thus, many interneurons preferentially innervate the perisomatic area and axon hillock of the pyramidal cells while others preferentially target dendritic branches and spines. Methods to preferentially activate dendritic or somatic inhibitory synapses onto pyramidal neurons have been devised. By using these methods, the present work demonstrates that a stimulation pattern that induces long term potentiation (LTP) in excitatory synapses of the Schaffer collaterals is also capable of inducing distinct types of long term plastic changes in different classes of inhibitory synapses: Induction of long term depression (LTD) was seen in dendritic inhibitory synapses whereas LTP was observed in somatic inhibitory synapses. These findings suggest that inhibitory synapses arising from different interneuron classes may respond to the same stimulus according to their specific plastic potential enabling a spatial combinatorial pattern of inhibitory effects onto the pyramidal cell.
长期突触可塑性在兴奋性突触中得到了更广泛的研究，但它也是抑制性突触的一个特性。许多抑制性突触靶向CA1区的海马锥体神经元。它们起源于几类中间神经元，这些中间神经元细分了它们在锥体细胞上靶向的表面积。因此，许多中间神经元优先支配锥体细胞的胞体周围区域和轴突丘，而其他中间神经元则优先靶向树突分支和棘。已经设计出了优先激活锥体神经元上树突或体细胞抑制性突触的方法。通过使用这些方法，目前的研究表明，在Schaffer侧支兴奋性突触中诱导长期增强（LTP）的刺激模式也能够在不同类别的抑制性突触中诱导不同类型的长期可塑性变化：在树突抑制性突触中观察到长期抑制（LTD）的诱导，而在体细胞抑制性突触中观察到LTP。这些发现表明，来自不同中间神经元类别的抑制性突触可能根据其特定的可塑性潜能对相同的刺激做出反应，从而在锥体细胞上形成抑制作用的空间组合模式。
