Balaban P M, Korshunova T A, Bravarenko N I
Laboratory of Cellular Neurobiology of Learning, Institute of Higher Nervous Activity and Neurophysiology, Butlerova 5A, Moscow 117485, Russia.
Eur J Neurosci. 2004 Jan;19(2):227-33. doi: 10.1111/j.1460-9568.2003.03129.x.
We show that activation of a single serotonergic cell is sufficient to trigger long-term associative enhancement of synaptic input to the withdrawal interneuron in a simple network consisting of three interconnected identified cells in the nervous system of terrestrial snail Helix. 1,2-bis (2-aminophenoxy) Ethane-N,N,N',N'-tetraacetic acid (BAPTA) injection in the postsynaptic neuron abolishes the pairing-specific enhancement of synaptic input. Activation of a single modulatory cell that we used to reinforce the synaptic input induced an increase of the intracellular [Ca2+] in the ipsilateral withdrawal interneuron without any changes of its membrane potential or input resistance. Similar changes in intracellular [Ca2+] were observed in the same withdrawal interneuron under bath application of 10(-5) m serotonin. Responses to repeated glutamate applications to the soma of synaptically isolated withdrawal interneurons increased after 10 min of serotonin or thapsigargin bath application, but were absent in conditions of preliminary BAPTA intracellular injection, significantly decreased under heparin injection. Thus, activity of a single modulatory cell may mediate reinforcement via an increase of [Ca2+] in the postsynaptic cell in a simple network consisting of neurons with defined behavioural roles.
我们发现，在由陆生蜗牛Helix神经系统中三个相互连接的已鉴定细胞组成的简单网络中，单个5-羟色胺能细胞的激活足以触发对退缩中间神经元突触输入的长期联合增强。在突触后神经元中注射1,2-双(2-氨基苯氧基)乙烷-N,N,N',N'-四乙酸(BAPTA)可消除突触输入的配对特异性增强。我们用于增强突触输入的单个调制细胞的激活，导致同侧退缩中间神经元细胞内[Ca2+]增加，而其膜电位或输入电阻没有任何变化。在浴用10(-5) m 5-羟色胺的情况下，在同一个退缩中间神经元中观察到细胞内[Ca2+]的类似变化。在对突触分离的退缩中间神经元的胞体重复施加谷氨酸后，在浴用5-羟色胺或毒胡萝卜素10分钟后反应增强，但在预先进行细胞内注射BAPTA的情况下反应消失，在注射肝素的情况下反应显著降低。因此，在由具有明确行为作用的神经元组成的简单网络中，单个调制细胞的活动可能通过增加突触后细胞内的[Ca2+]来介导强化作用。
