Lewis J, Bachoo M, Polosa C, Glass L
Department of Physiology, McGill University, Montreal, Que., Canada.
Brain Res. 1990 May 28;517(1-2):44-50. doi: 10.1016/0006-8993(90)91005-2.
The effect of brief superior laryngeal nerve stimulation on the respiratory rhythm was investigated in midcollicular decerebrate, unanesthetized, artificially ventilated, paralysed, vagotomized and debuffered cats. Stimulus trains (50 ms, 200 Hz) delivered during inspiration (I) with intensities exceeding a threshold value, that was inversely related to the phase of the cycle, terminated I and shortened the following expiration (E) (irreversible I termination). Stimulus trains given during I with intensities just below this threshold value produced a transient suppression of I followed by resumption of activity, resulting in a slight prolongation of both I and the following E (reversible I termination). Stimulation during E produced a phase-dependent prolongation of E, but did not affect the next I. Phase-resetting curves were constructed by measuring the changes in respiratory cycle duration produced by stimuli given at phases throughout the cycle. A single stimulus produced aftereffects that lasted several cycles. The aftereffects were investigated by delivering stimuli at a fixed delay from cycle onset every n cycles (n is an integer). Certain combinations of delay, stimulus intensity, and n, resulted in (1) a variable combination of reversible and irreversible I terminations, rather than a consistent response, and (2) an increase in cycle duration. The stimulus aftereffects, that can last up to 9 cycles, may account for previously described unpredictability in the response of the respiratory oscillator to a given stimulus.
在中脑去大脑、未麻醉、人工通气、麻痹、迷走神经切断且缓冲减弱的猫身上，研究了短暂喉上神经刺激对呼吸节律的影响。在吸气（I）期间给予刺激串（50毫秒，200赫兹），其强度超过与周期相位呈反比的阈值时，会终止吸气并缩短随后的呼气（E）（不可逆的吸气终止）。在吸气期间给予强度略低于该阈值的刺激串会导致吸气的短暂抑制，随后恢复活动，导致吸气和随后的呼气均略有延长（可逆的吸气终止）。在呼气期间进行刺激会导致呼气出现相位依赖性延长，但不影响下一次吸气。通过测量在整个周期的各个相位给予刺激所产生的呼吸周期持续时间的变化来构建相位重置曲线。单个刺激会产生持续几个周期的后效应。通过每隔n个周期（n为整数）从周期开始处以固定延迟给予刺激来研究后效应。延迟、刺激强度和n的某些组合会导致：（1）可逆和不可逆吸气终止的可变组合，而非一致的反应；（2）周期持续时间增加。持续长达9个周期的刺激后效应，可能解释了先前描述的呼吸振荡器对给定刺激反应中的不可预测性。
