In vitro formation and activity-dependent plasticity of synapses between Helix neurons involved in the neural control of feeding and withdrawal behaviors
In vitro formation and activity-dependent plasticity of synapses between Helix neurons involved in the neural control of feeding and withdrawal behaviors
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DOI：
10.1016/j.neuroscience.2005.05.021
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发表时间：
2005-01-01
期刊：
影响因子：
3.3
通讯作者：
Ghirardi, M
中科院分区：
文献类型：
--
作者：
Fiumara, F;Leitinger, G;Ghirardi, M
短期活动依赖性突触可塑性在神经系统的短期记忆和信息处理中具有重要作用。尽管控制螺旋属陆地蜗牛不同行为的神经元回路已经得到了一些细节的表征，但人们对调节特定行为行为的已识别神经元之间突触的活动依赖性可塑性知之甚少。为了研究与异质突触影响无关的行为相关螺旋突触的同突触活性依赖性可塑性，我们试图在细胞培养物中重建它们。为此，我们首先在培养物中研究调节螺旋神经元之间突触形成的因素，然后研究体外重建的参与唾液分泌和全身撤回的神经控制的单突触连接的短期可塑性。我们发现，独立于外在因素，细胞间相互作用似乎足以触发电突触和化学突触的形成，尽管对于体内突触连接而言，其类型或关联大多不合适。培养基中神经节衍生因子的存在是在体外重建适当的体内样连接所必需的，通过减少电连接的发生并促进化学兴奋性突触的形成，同时显然不影响抑制性连接的形成。这些不耐热因子通过不同的蛋白酪氨酸激酶信号转导途径调节电和化学突触发生。利用体外重建的突触，我们发现喂养型中间神经元-传出神经元突触和机械感觉神经元-撤回型中间神经元突触表现出多种形式的短期增强样促进、增强和强直后增强以及同突触抑制。这些形式的可塑性被认为与 Helix 进食和退缩行为的调节有关，通过诱导高阶中间神经元的输入和输出突触强度的剧烈活动依赖性变化，在 Helix 行为层次的控制中发挥着至关重要的作用。 (c) 2005 年由 Elsevier Ltd 代表 IBRO 出版。
Short-term activity-dependent synaptic plasticity has a fundamental role in short-term memory and information processing in the nervous system. Although the neuronal circuitry controlling different behaviors of land snails of the genus Helix has been characterized in some detail, little is known about the activity-dependent plasticity of synapses between identified neurons regulating specific behavioral acts. In order to study homosynaptic activity-dependent plasticity of behaviorally relevant Helix synapses independently of heterosynaptic influences, we sought to reconstruct them in cell culture. To this aim, we first investigated in culture the factors regulating synapse formation between Helix neurons, and then we studied the short-term plasticity of in vitro-reconstructed monosynaptic connections involved in the neural control of salivary secretion and whole-body withdrawal. We found that independently of extrinsic factors, cell-cell interactions are seemingly sufficient to trigger the formation of electrical and chemical synapses, although mostly inappropriate-in their type or association-with respect to the in vivo synaptic connectivity. The presence of ganglia-derived factors in the culture medium was required for the in vitro reestablishment of the appropriate in vivo-like connectivity, by reducing the occurrence of electrical connections and promoting the formation of chemical excitatory synapses, while apparently not influencing the formation of inhibitory connections. These heat-labile factors modulated electrical and chemical synaptogenesis through distinct protein tyrosine kinase signal transduction pathways. Taking advantage of in vitro-reconstructed synapses, we have found that feeding interneuron-efferent neuron synapses and mechanosensory neuron-withdrawal interneuron synapses display multiple forms of short-term enhancement-like facilitation, augmentation and posttetanic potentiation as well as homosynaptic depression. These forms of plasticity are thought to be relevant in the regulation of Helix feeding and withdrawal behaviors by inducing dramatic activity-dependent changes in the strength of input and output synapses of high-order interneurons with a crucial role in the control of Helix behavioral hierarchy. (c) 2005 Published by Elsevier Ltd on behalf of IBRO.