ACTION-POTENTIAL DURATION AND THE MODULATION OF TRANSMITTER RELEASE FROM THE SENSORY NEURONS OF APLYSIA IN PRESYNAPTIC FACILITATION AND BEHAVIORAL SENSITIZATION
ACTION-POTENTIAL DURATION AND THE MODULATION OF TRANSMITTER RELEASE FROM THE SENSORY NEURONS OF APLYSIA IN PRESYNAPTIC FACILITATION AND BEHAVIORAL SENSITIZATION
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DOI：
10.1073/pnas.83.21.8410
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发表时间：
1986-11-01
影响因子：
11.1
通讯作者：
KANDEL, ER
中科院分区：
文献类型：
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作者：
HOCHNER, B;KLEIN, M;KANDEL, ER
海兔感觉神经元的突触前促进递质释放是鳃和虹吸撤回反射行为敏化的重要贡献者。释放的增强伴随着感觉神经元中血清素敏感的 S 电流的减少，以及随之而来的突触前动作电位持续时间的增加（范围从 10% 到 30%）。我们发现，完整腹部神经节中感觉神经元去极化电压钳步骤的持续时间发生类似幅度的变化，突触电位会增加 45-120%。在分离的细胞培养物中，这些变化导致突触电位增加 25-60%。使用电压钳延长突触前去极化或通过 K+ 通道阻滞剂延长动作电位持续时间会导致突触电位达到峰值的时间延长；在突触前促进过程中，峰值时间也会发生类似的变化。同突触抑制或改变 Ca2+ 浓度不会改变达峰时间，这些过程会改变释放而不改变动作电位的持续时间。通过对突触前神经元进行电压钳位来防止尖峰变宽，可以显着减少或阻止促进作用。这些结果表明，促进过程中动作电位的拓宽是递质释放增强的一个因果因素。
Presynaptic facilitation of transmitter release from Aplysia sensory neurons is an important contributor to behavioral sensitization of the gill and siphon withdrawal reflex. The enhanced release is accompanied by reduction of the serotonin-sensitive S current in the sensory neurons and a consequent increase in duration of the presynaptic action potential (ranging from 10% to 30%). We find that changes of similar magnitude in the duration of depolarizing voltage-clamp steps in sensory neurons in intact abdominal ganglia yield increases in synaptic potentials of 45-120%. In dissociated cell culture these changes lead to increases of 25-60% in the synaptic potential. Prolongation of presynaptic depolarization using voltage clamp or prolongation of the duration of the action potential by K+-channel blockers leads to prolongation of the time-to-peak of the synaptic potentials; similar changes in time-to-peak occur during presynaptic facilitation. The time-to-peak is not changed by homosynaptic depression or by changing the Ca2+ concentration, procedures that alter release without changing the duration of the action potential. Preventing the spike from broadening by voltage clamping the presynaptic neuron substantially reduces or blocks the facilitation. These results suggest that broadening of the action potential during facilitation is a causal factor in the enhancement of transmitter release.