Gidda J S, Goyal R K
Gastroenterology. 1985 Oct;89(4):843-51. doi: 10.1016/0016-5085(85)90582-7.
The influence of two successive vagal stimuli on esophageal contractions was studied by recording intraluminal pressures in the smooth muscle portion of the opossum esophagus. The esophageal contraction in response to the first or second stimulus in a pair of vagal stimuli was inhibited depending on the interstimulus interval, the frequency of the stimulus, and the esophageal site. The esophageal contraction in response to the first vagal stimulus was inhibited by a second vagal stimulus if the latter stimulus was applied before the peak of the first contraction. This phenomenon is termed initial inhibition. Initial inhibition is a graded phenomenon. It was greater at higher frequencies than at lower frequencies (p less than 0.001), and was significantly greater in the distal esophagus than in the proximal esophagus (p less than 0.01). The term "refractoriness" has been used to denote inhibition of the second esophageal contraction by the first. Refractoriness was observed during and beyond the duration of the first esophageal response. Refractoriness was also observed at all esophageal levels; however, the interstimulus intervals that demonstrated refractoriness were significantly greater in the distal than in the proximal esophagus (p less than 0.01). Refractoriness was complete (effective refractory period) during the ascending phase of the first contraction. Refractoriness was incomplete after the peak of the contraction (relative refractory period). These studies show gradients of durations and degrees of initial inhibition and refractoriness along the esophagus. The gradient is responsible for the peristaltic nature of esophageal contraction. The gradients of initial inhibition and refractoriness determine esophageal response to multiple successive swallows.
通过记录负鼠食管平滑肌段的腔内压力，研究了连续两次迷走神经刺激对食管收缩的影响。一对迷走神经刺激中，第一次或第二次刺激引起的食管收缩会根据刺激间隔、刺激频率和食管部位受到抑制。如果第二次迷走神经刺激在第一次收缩的峰值之前施加，那么它会抑制第一次迷走神经刺激引起的食管收缩。这种现象被称为初始抑制。初始抑制是一种分级现象。在较高频率下比在较低频率下更明显（p<0.001），并且在食管远端比在食管近端明显更明显（p<0.01）。“不应期”一词已被用于表示第一次对第二次食管收缩的抑制。在第一次食管反应期间及之后都观察到了不应期。在食管的所有水平也都观察到了不应期；然而，显示不应期的刺激间隔在食管远端比在食管近端明显更长（p<0.01）。在第一次收缩的上升阶段，不应期是完全的（有效不应期）。在收缩峰值之后，不应期是不完全的（相对不应期）。这些研究表明，沿食管存在初始抑制和不应期的持续时间及程度梯度。这种梯度决定了食管收缩的蠕动性质。初始抑制和不应期的梯度决定了食管对多次连续吞咽的反应。
