Acta Scientiarum Naturalium Universitatis Pekinensis

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Conductance Modulation Mechanism of Positional Discrimination on the Synapse of AP Neuron in Leech

XIONG Weihong, ZHANG Renji   

  1. College of Life Sciences, Peking University, Beijing, 100871
  • Received:1997-12-21 Online:1998-07-20 Published:1998-07-20


熊卫红, 张人骥   

  1. 北京大学生命科学学院,北京,100871

Abstract: This paper revealed that the different strength of synapses on AP neuron can be shown by the mechanical stimulation applied on the skin surface in the neighbouring segment of a ganglion-body wall preparation in the leech Whitmania pigra. The comparisons were made (1) on the effect of receptive neuron evoked by mechanical stimuli in different annuli of the same segment, (2) on the postsynaptic effects of AP neuron evoked by the same mechanical stimuli in different annuli and (3) also in a single annulus of the segment evoked by the same stimuli in different positions. It is established that the synapses of AP neuron function in positional discrimination and integration by synaptic strength.The authors use double voltage clamp in both the pre-synaptic T neuron and the post-synaptic AP neuron in situ showed that the synaptic strength of AP neuron was modulated mainly by the different conductance of its electrical synaptic transmission. The synaptic conductance between T and AP neurons is modulated by the difference of membrane potential between T and AP neurons. By this mechanism electrical synapses of AP neuron can transform the position information of reception into the spatial discrimination of perception.

Key words: leech, annulus, AP neuron, electrical synapse, positional discrimination, conductance modulation

摘要: 用神经节-体壁标本,揭示AP神经元对邻节机械感受神经元传入信号也具有部位分辨机能。比较同一感受野内逐个体环的传入效应;比较不同体环同一部位、及单一体环不同部位分别对同一AP的突触后效应;确证AP涉及知觉机制,其电突触具有部位分辨与整合功能。突触前、后原位胞内双电压箝揭示:AP神经元电突触部位分辨主要由电突触传递的电导不同引起,T与AP神经元间电突触电导受膜电位调控。AP电突触可将感受部位信号转换成对刺激空间知觉辨识。

关键词: 水蛭, 体环, AP神经元, 电突触, 部位分辨, 电导调制

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