Duan Kailai, Yu Xiao, Zhang Chen, Zhou Zhuan
Institute of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China.
J Neurosci. 2003 Dec 3;23(35):11235-43. doi: 10.1523/JNEUROSCI.23-35-11235.2003.
Action potentials (APs) are the principal physiological stimuli for neurotransmitter secretion in neurons. Most studies on stimulus-secretion coupling have been performed under voltage clamp using artificial electrical stimuli. To investigate the modulatory effects of AP codes on neural secretion, we introduce a capacitance method to study AP-induced secretion in single cells. The action potential pattern was defined by a four-parameter "code function:" F(n, m, f, d). With this method, cell secretion evoked by stimulation with an AP code was quantified in real time by membrane capacitance (Cm) in adrenal chromaffin cells. We found, in addition to AP frequency (f), for a given number of APs, another parameter of the AP code, the number of AP bursts (m) in which the set of APs occurs, can effectively modulate cell secretion. Possible mechanisms of the m effect are depletion of the readily releasable pool and inactivation of Ca2+ channels during a burst of APs. The physiological m effect may play a key role in AP-mediated neural information transfer within a single neuron and among the elements of a neural network.
动作电位（APs）是神经元中神经递质分泌的主要生理刺激因素。大多数关于刺激-分泌偶联的研究都是在电压钳制条件下使用人工电刺激进行的。为了研究AP编码对神经分泌的调节作用，我们引入了一种电容方法来研究单细胞中AP诱导的分泌。动作电位模式由一个四参数“编码函数”：F(n, m, f, d)定义。使用这种方法，通过肾上腺嗜铬细胞中的膜电容（Cm）实时定量由AP编码刺激引起的细胞分泌。我们发现，除了AP频率（f）外，对于给定数量的AP，AP编码的另一个参数，即AP爆发（m）的数量（一组AP出现的次数），可以有效地调节细胞分泌。m效应的可能机制是在AP爆发期间易释放池的耗尽和Ca2+通道的失活。生理m效应可能在单个神经元内以及神经网络元件之间的AP介导的神经信息传递中起关键作用。
