Individual prepacemaker neurons can modulate the pacemaker cycle of the gymnotiform electric fish, Eigenmannia.
Individual prepacemaker neurons can modulate the pacemaker cycle of the gymnotiform electric fish, Eigenmannia.
复制标题
单个前起搏器神经元可以调节裸形电鱼 Eigenmannia 的起搏器周期。
DOI：
10.1007/bf01342699
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发表时间：
1988
期刊：
影响因子：
--
通讯作者：
Heiligenberg,W
中科院分区：
文献类型：
--
作者：
Kawasaki,M;Heiligenberg,W
裸形电鱼中脑的前起搏核（PPN）为髓质起搏核提供唯一已知的神经元输入，该核通过单个命令脉冲触发每个电器官放电（EOD）周期。 PPN 的电刺激引起起搏器活动的两种不同形式的调制：短暂的加速（因此被称为“鸣叫声”）和时间常数约为一秒的逐渐频率变化。相关的 EOD 调制与自然通信信号无法区分。根据刺激部位的不同，两种形式的调节可以单独引发或叠加（图 1）。仅引起线性调频的刺激位点与仅引起逐渐移动的位点之间的距离可小至 60 μm。引发的鸣叫声的幅度取决于相对于起搏器周期相位的脉冲刺激的时间（图 2、3）。单个 PPN 神经元的细胞外和细胞内记录表明，单个神经元的动作电位会产生鸣叫声，并且鸣叫声的幅度取决于相对于起搏器周期相位的动作电位的时间（图 4、5）。这些神经元的尖峰活动与干扰回避反应 (JAR) 无关，表明鸣叫声和 JAR 具有独立的神经元机制。通过电流注射使这些神经元去极化，产生脉冲串（图 6），细胞内注射荧光黄将这些细胞识别为一种大型 PPN 神经元，也可以用辣根过氧化物酶（HRP）从起搏器逆行标记（图 7）。尽管在实验过程中不断引发 JAR，但我们无法记录与起搏器频率逐渐变化相关的神经元。 PPN 的较小细胞类型可以用 HRP 逆行标记，但迄今为止无法记录，可能会控制逐渐的频率偏移。
The prepacemaker nucleus (PPN) in the midbrain of the gymnotiform electric fishEigenmanniaprovides the only known neuronal input to the medullary pacemaker nucleus, which triggers each electric organ discharge (EOD) cycle by a single command pulse. Electrical stimulation of the PPN elicited two distinct forms of modulations in the pacemaker activity, brief accelerations, hence referred to as ‘chirps’, and gradual frequency shifts with a time constant of approximately one second. The associated EOD modulations were indistinguishable from natural communication signals. Depending upon the site of stimulation, the two forms of modulation could be elicited alone or superimposed (Fig. 1). Stimulation sites eliciting only chirps could be separated from sites eliciting only gradual shifts by as little as 60 μm. The magnitude of the elicited chirps depended upon the timing of the pulse stimulus with reference to the phase of the pacemaker cycle (Figs. 2, 3).Extracellular and intracellular recordings of single PPN neurons revealed that an action potential from a single neuron generates a chirp, and that the magnitude of the chirp depends upon the timing of the action potential with reference to the phase of the pacemaker cycle (Figs. 4, 5). The spike activity of these neurons had no relation to the jamming avoidance response (JAR), suggesting independent neuronal mechanisms for chirps and the JAR. Depolarization of such neurons by current injection produced bursts of chirps (Fig. 6), and intracellular injection of Lucifer Yellow identified these cells as a large type of PPN neuron which could also be retrogradely labeled from the pacemaker with horseradish peroxidase (HRP) (Fig. 7). We were unable to record from neurons linked to gradual shifts of the pacemaker frequency, although the JAR was elicited continually during the experiments. A smaller cell type of the PPN which can be retrogradely labeled with HRP but so far could not be recorded may control gradual frequency shifts.