Reconfiguration of multiple motor networks by short- and long-term actions of an identified modulatory neuron
Reconfiguration of multiple motor networks by short- and long-term actions of an identified modulatory neuron
复制标题
DOI：
10.1111/j.1460-9568.2005.04442.x
复制
发表时间：
2005-11-01
影响因子：
3.4
通讯作者：
Simmers, J
中科院分区：
文献类型：
--
作者：
Faumont, S;Combes, D;Simmers, J
幽门和胃运动模式生成网络在口胃神经节的龙虾Homarus gammarus重新配置成一个新的功能电路的突发放电在一个确定的对调制投射中间神经元，最初命名为幽门抑制（PS）神经元，因为它们对幽门网络活动的抑制作用。在这里，我们阐明的PS神经元对邻近的胃电路的个别成员的行动，以及描述他们的能力，改变两个网络之间的突触耦合。PS神经元放电对胃网络活动有两种不同的影响：一个初始的短暂的行动介导的大多数胃运动神经元的短暂抑制，随后由一个长期持久的电路激活与延长PS诱发的去极化的内侧胃（MG）运动神经元和单个网络interneuron，Int 1。这些持久的影响是电压依赖性的，超极化电流注入和光消融实验表明，MG神经元和Int 1的兴奋是PS引起的胃网络节律性的关键。并行地，PS神经元放电持续（持续几分钟）增强MG神经元对幽门扩张器（PD）-前突（AB）起搏神经元的抑制性突触影响的强度，从而促进两个网络的操作融合。因此，单个调节神经元可以通过一系列非常不同且高度靶向特异性的机制来影响不同的神经元群体：传统的瞬时突触驱动和膜特性和突触功效的上调或下调。此外，这些动作的明显不同的时间过程允许通过给定的调制输入顺序地指定不同的电路配置。
The pyloric and gastric motor pattern-generating networks in the stomatogastric ganglion of the lobster Homarus gammarus are reconfigured into a new functional circuit by burst discharge in an identified pair of modulatory projection interneurons, originally named the pyloric suppressor (PS) neurons because of their inhibitory effects on pyloric network activity. Here we elucidate the actions of the PS neurons on individual members of the neighbouring gastric circuit, as well as describing their ability to alter synaptic coupling between the two networks. PS neuron firing has two distinct effects on gastric network activity: an initial short-lasting action mediated by transient inhibition of most gastric motoneurons, followed by a long-lasting circuit activation associated with a prolonged PS-evoked depolarization of the medial gastric (MG) motoneuron and the single network interneuron, Int1. These long-lasting effects are voltage-dependent, and experiments with hyperpolarizing current injection and photoablation suggest that excitation of both the MG neuron and Int1 is critical for PS-elicited gastric network rhythmicity. In parallel, PS neuron discharge persistently (lasting several minutes) enhances the strength of an inhibitory synaptic influence of the MG neuron on the pyloric dilator (PD)-anterior burster (AB) pacemaker neurons, thereby facilitating operational fusion of the two networks. Therefore, a single modulatory neuron may influence disparate populations of neurons via a range of very different and highly target-specific mechanisms: conventional transient synaptic drive and up- or down-modulation of membrane properties and synaptic efficacy. Moreover, distinctly different time courses of these actions allow different circuit configurations to be specified sequentially by a given modulatory input.