Wang Gui-Min, Song Gang, Zhang Heng
Institute of Physiology, School of Medicine, Shandong University, Jinan 250012, China;E-mail:
Sheng Li Xue Bao. 2005 Aug 25;57(4):511-6.
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, 20-60 muA, 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 (f) 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.
本研究的目的是探讨通过60秒的迷走神经电刺激模拟的黑林-布雷尔（HB）反射中的学习与记忆。在兔中观察膈神经放电对迷走神经电刺激（10 - 100 Hz，20 - 60 μA，脉冲持续时间0.3 ms，持续60秒）的反应。结果表明，60秒的迷走神经刺激产生了经典的HB反射，其由两个成分组成——肺充气反射（即吸气抑制）和肺放气反射（即吸气易化）。（1）迷走神经中枢端的高频刺激（≥40 Hz，60秒）导致吸气相缩短和呼气相延长。在持续迷走神经刺激期间，对膈神经放电的抑制作用逐渐解除，表明抑制的习惯化。刺激停止时，膈神经放电出现刺激后短暂反弹。迷走神经中枢端的低频刺激（<40 Hz，60秒）导致呼吸频率（f）增加和呼气相缩短。在迷走神经刺激期间，对膈神经放电的兴奋作用也逐渐解除。去除迷走神经刺激后，膈神经放电逐渐恢复到对照水平，表明短期增强（STP）。（2）HB反射的习惯化与刺激强度和频率呈负相关。随着刺激频率或强度增加，习惯化程度降低。另一方面，随着刺激强度和频率降低，习惯化程度增加。这些数据表明在迷走神经刺激模拟的HB反射中存在非联合学习现象。兔呼吸反射控制中可能存在神经突触可塑性和适应性。
