ELECTRICALLY COUPLED PACEMAKER NEURONS RESPOND DIFFERENTLY TO SAME PHYSIOLOGICAL INPUTS AND NEUROTRANSMITTERS
ELECTRICALLY COUPLED PACEMAKER NEURONS RESPOND DIFFERENTLY TO SAME PHYSIOLOGICAL INPUTS AND NEUROTRANSMITTERS
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DOI：
10.1152/jn.1984.51.6.1362
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发表时间：
1984-01-01
影响因子：
2.5
通讯作者：
EISEN, JS
中科院分区：
文献类型：
--
作者：
MARDER, E;EISEN, JS
2个幽门扩张器（PD）运动神经元和单个前爆发放电（AB）中间神经元电耦合在一起，共同构成了龙虾（Panulirus interruptus）口胃神经节幽门中枢模式发生器的起搏器。AB神经元是一种内源性爆发放电神经元，而PD神经元是一种条件性爆发放电神经元。利用荧光黄光灭活技术研究了生理输入和神经递质对分离的PD神经元和AB神经元的影响。高频刺激下心室下神经（IVN）纤维在AB和PD神经元中引发三相反应：快速兴奋性突触后电位（EPSP），随后是缓慢抑制性突触后电位（IPSP），接着是起搏器慢波去极化的增强。光灭活实验表明，慢波的增强主要是由于IVN纤维对PD神经元而非AB神经元的作用。浴槽施加多巴胺显著改变幽门系统的运动输出。光灭活实验表明，10⁻⁴M多巴胺增加AB神经元中记录到的慢波去极化的幅度和频率，但使PD神经元超极化并抑制它。浴槽施加血清素[5 - 羟色胺]增加AB神经元中慢波去极化的频率和幅度，但对PD神经元没有影响。毛果芸香碱，一种毒蕈碱型胆碱能激动剂，刺激PD神经元和AB神经元中的慢波去极化产生，但所引发的慢波的波形和频率非常不同。尽管电耦合的PD和AB神经元总是同步去极化，并共同作为幽门系统的起搏器，但它们对神经元输入和几种假定的神经调节剂的反应不同。尽管电耦合足以确保同步活动，但PD和AB神经元可以被独立调节。
The 2 pyloric dilator (PD) motor neurons and the single anterior burster (AB) interneuron are electrically coupled and together comprise the pacemaker for the pyloric central pattern generator of the stomatogastric ganglion of the lobster, Panulirus interruptus. The AB neuron is an endogenously bursting neuron, while the PD neuron is a conditional burster. The effects of physiological inputs and neurotransmitters on isolated PD neurons and AB neurons were studied using the lucifer yellow photoinactivation technique. Stimulation of the inferior ventricular nerve (IVN) fibers at high frequencies elicits a triphasic response in AB and PD neurons: a rapid excitatory postsynaptic potential (EPSP) followed by a slow inhibitory postsynaptic potential (IPSP), followed by an enhancement of the pacemaker slow-wave depolarizations. Photoinactivation experiments indicate that the enhancement of the slow wave is due primarily to actions of the IVN fibers on the PD neurons but not on the AB neuron. Bath-applied dopamine dramatically alters the motor output of the pyloric system. Photoinactivation experiments show that 10-4 M dopamine increases the amplitude and frequency of the slow-wave depolarizations recorded in the AB neuron but hyperpolarizes and inhibits the PD neurons. Bath-applied serotonin [5-hydroxytryptamine] increases the frequency and amplitude of the slow-wave depolarizations in the AB neuron but has no effect on PD neurons. Pilocarpine, a muscarinic cholinergic agonist, stimulates slow-wave depolarization production in both PD neurons and the AB neuron, but the waveform and frequency of the slow waves elicited are quite different. Although the electrically coupled PD and AB neurons always depolarize synchronously and act together as the pacemaker for the pyloric system, they respond differently to a neuronal input and to several putative neuromodulators. Despite electrical coupling sufficient to ensure synchronous activity, the PD and AB neurons can be modulated independently.