摘要
本文旨在研究电刺激家兔迷走神经诱导的黑-伯(Hering-Breuer,HB)反射中的学习和记忆现象.选择性电刺激家兔迷走神经中枢端(频率10～100 Hz,强度20～60 μA,波宽0.3 ms,持续60 s),观察对膈神经放电的影响.以不同频率电刺激家兔迷走神经可模拟HB反射的两种成分,即类似肺容积增大所致抑制吸气的肺扩张反射和类似肺容积缩小所致加强吸气的肺萎陷反射.(1)长时高频(≥40 Hz,60 s)电刺激迷走神经可模拟呼吸频率减慢,呼气时程延长的肺扩张反射.随着刺激时间的延长,膈神经放电抑制的程度逐渐衰减,表现为呼吸频率的减慢(主要由呼气时程延长所致)在刺激过程中逐渐减弱或消失,显示为适应性或'习惯化'的现象;刺激结束时呼吸运动呈现反跳性增强,表现为一过性的呼气时程缩短,呼吸频率加快,然后才逐渐恢复正常.长时低频(＜40 Hz,60 s)电刺激迷走神经可模拟呼吸频率加快、呼气时程缩短的肺萎陷反射.随着刺激时间的延长,膈神经放电增强的程度逐渐衰减,同样表现出'习惯化'现象;刺激结束后,膈神经放电不是突然降低,而是继续衰减,表现为呼气时程逐渐延长,呼吸频率逐渐减慢,直至恢复到前对照水平,表现了刺激后的短时增强效应.(2)HB反射的适应性或'习惯化'程度反向依赖于刺激强度和刺激频率,表现为随着刺激强度和频率的增加,膈神经放电越远离正常基线水平,即习惯化程度减弱.结果表明,家兔HB反射具有'习惯化'这一非联合型学习现象,反映与其有关的呼吸神经元网络具有突触功能的可塑性,呼吸的中枢调控反射具有一定的适应性.
The purpose of this study was to explore learning and memory in the Hering-Breuer （HB） reflex simulated by a 60-second-long electrical stimulation of vagus nerve. The responses of phrenic nerve discharge to electrical stimulation （10～100 Hz, 20～60μA, pulse duration 0.3 ms, for 60 s） of the vagus nerve were observed in rabbits. The results showed that 60-second-long stimulation of vagus nerve produced classic HB reflex, which is composed of two components -- lung inflation reflex that is the inhibition of inspiration, and lung deflation reflex that is the facilitation Of inspiration. （1） High frequency stimulation （≥ 40 Hz, 60 s） of the central end of vagus nerve induced shortening of the inspiratory phase and lengthening of expiratory duration. The inhibitory effect on phrenic discharge was released gradually during sustained vagal stimulation, indicating the habituation of the inhibition. At the cessation of stimulation, the phrenic discharge showed transient post-stimulus rebound. Low frequency stimulation （〈40 Hz, 60 s） of the central end of vagus nerve caused an increase in respiratory frequency （1） and shortening of expiratory duration. The excitatory effect on phrenic discharge was also released gradually during the vagal stimulation.The phrenic discharge returned to control level gradually after the removal of the vagal stimulus, indicating short-term potentiation （STP）. （2）The habituation of HB reflex was inversely dependent on stimulus intensity and frequency. With an increase in the stimulus frequency or intensity, the degree of the habituation decreased. On the other hand, with the decrease of stimulation intensity and frequency, the degree of the habituation increased. These data indicate a phenomenon of non-associative learning in HB reflex simulated by vagal stimulation. Neural synaptic plasticity and accommodation may exist in the reflex control of respiration in rabbits.
出处
《生理学报》
CAS
CSCD
北大核心
2005年第4期511-516,共6页
Acta Physiologica Sinica
基金
This work was supported by the Ministry of Education of China (No.413018) and Youth Science Foundation of Health Bureau ofShandong Province (No. 2003-21).
关键词
学习
黑-伯反射
家兔
learning
Hering-Breuer reflex
rabbits
