GRADED SYNAPTIC TRANSMISSION BETWEEN LOCAL INTERNEURONES AND MOTOR NEURONS IN THE METATHORACIC GANGLION OF THE LOCUST
GRADED SYNAPTIC TRANSMISSION BETWEEN LOCAL INTERNEURONES AND MOTOR NEURONS IN THE METATHORACIC GANGLION OF THE LOCUST
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DOI：
10.1113/jphysiol.1978.sp012569
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发表时间：
1978-01-01
影响因子：
5.5
通讯作者：
SIEGLER, MVS
中科院分区：
文献类型：
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作者：
BURROWS, M;SIEGLER, MVS
1.在蝗虫的后胸神经节中，一些神经元可以影响已识别的突触后运动神经元的膜电位的变化，而自身不产生尖峰。2.这些“非尖峰”神经元仅在后胸神经节内具有突起，因此是局部神经节内的中间神经元。3.中间神经元中没有尖峰反映了它们的正常生理状态，而不是由于实验条件。4.当中间神经元被持续几百毫秒的电流脉冲注射去极化时，突触后运动神经元在脉冲的持续时间内被去极化或超极化。5.突触后电压的变化幅度根据突触前电流的大小分级。6.许多生理实验表明，对运动神经元的分级效应是由化学突触传递介导的。例如，运动神经元的诱发超极化可以通过用注入的电流同时超极化运动神经元来反转极性。7.在静息电位下，一些中间神经元紧张性地释放足够的递质，以产生可测量的突触后效应。向这些中间神经元中注入去极化和超极化电流会导致突触后电位发生相反的变化。8.其他的中间神经元在观察到突触后效应之前必须从静息电位去极化，而超极化电流没有突触后效应。在这些中间神经元中，估计仅2mV的去极化就足以影响递质的释放。9.在后肢主动运动期间，非尖峰中间神经元的膜电位可波动高达15 mV，并且可记录高达5 mV的单个p.s.p.s。因此，总p.s.p.s或甚至单个p.s.p. s被认为是影响这些中间神经元释放递质的电生理信号。
1. In the metathoracic ganglion of the locust some neurones can effect changes in the membrane potential of identified post‐synaptic motor neurones without themselves spiking. 2. These 'non‐spiking' neurones have processes only within the metathoracic ganglion, and therefore are local intraganglionic interneurones. 3. The absence of spikes in the interneurones reflects their normal physiological state and is not due to the experimental conditions. 4. When the interneurones are depolarized by the injection of current pulses lasting several hundred milliseconds, post‐synaptic motor neurones are either depolarized, or hyperpolarized, for the duration of the pulse. 5. The magnitude of the change in post‐synaptic voltage is graded according to the amount of presynaptic current. 6. A number of physiological tests indicate that the graded effects upon motor neurones are mediated by chemical synaptic transmission. For example, an evoked hyperpolarization of a motor neurone can be reversed in polarity by simultaneously hyperpolarizing the motor neurone with injected current. 7. At their resting potential some interneurones tonically release sufficient transmitter to have a measurable post‐synaptic effect. The injection of depolarizing and hyperpolarizing currents into these interneurones effects opposite changes in post‐synaptic potential. 8. Other interneurones must be depolarized from resting potential before a post‐synaptic effect is observed, and hyperpolarizing currents have no post‐synaptic effect. In these interneurones it is estimated that a depolarization of only 2 mV is sufficient to effect the release of transmitter. 9. The membrane potentials of non‐spiking interneurones can fluctuate by as much as 15 mV during active movements of the hind legs and individual p.s.p.s as large as 5 mV can be recorded. Therefore, summed p.s.p.s or even single ones are expected to be the electrophysiological signals effecting transmitter release from these interneurones.