目的：明确食管扩张时下食管括约肌发生松弛状态下胃食管反流的发生率。方法：12例健康志愿者在餐前和餐后同时检测食管压力和pH，食管扩张是通过快速和缓慢的气体注射诱发。结果：引起完全的下食管扩约肌松弛的气体阈值量平均为（11.0±1.0）ml。只有极少的松弛伴有继发蠕动。快速注气下食管括约肌的松弛时间为（13.0±1.5）s；慢速注射时食管括约肌的松弛时间是（16.0±2.0）s。由快速阈值量气体注射引超LES松弛并伴有胃食管反流率，在餐后为（22±6）%；缓慢注射时为（23±10）%。对于快速食管扩张，单独的下食管括约肌松弛伴随反流的百分比显著高于伴有继发蠕动的下食管括约肌松弛时出现的胃食管反流情况。结论：（1）胃食管反流可以发生在由食管扩张引起的下食管括约肌松弛期内；（2）食管扩张可以引起不伴随继发蠕动的单纯下食营括约肌松弛：（3）单纯下食菅括约肌松弛时的胃食管反流发生率显著高于伴有继发蠕动的情况。

Pressures generated by the pharyngeal constrictor muscles and proximal esophagus involve acetylcholine-induced muscle contractions. We hypothesized that the pharyngo-esophageal pressure gradient is related to choline acetyltransferase activity. In nine anesthetized cats, hypopharyngeal pressure and proximal esophageal pressure were recorded with a solid state transducer assembly. Enzymatic activities in the thyropharyngeus. cricopharyngeus, and proximal esophageal muscles were measured. Hypopharyngeal pressure was higher than the proximal esophagus (P<0.01), and choline acetyltransferase activity was higher in the cricopharyngeus compared to the proximal esophagus (P<0.05). The pressure gradient between the hypopharynx and proximal esophagus may be influenced by the activity of choline acetyltransferase.

Objective To determine the effect of ageing on length and resting pressure of the upper and lower oesophageal sphincters (UOSs, LOSs). Background The effectiveness of upper and lower oesophageal sphincters (UOSs and LOSs, respectively) in the control of retrograde trans-sphincteric flow is influenced by sphincteric pressure and length. Methods Nine young and nine elderly healthy volunteers were studied. Resting UOS and LOS pressures were measured by sleeve devices and lengths were measured by the station pull-through technique. Results The length of the UOS high pressure zone in the elderly (2.1

Effect of pharyngeal water stimulation on esophageal peristalsis and bolus transport. Am. J. Phvsiol. 272 (Gastrointest. Liver Physiol. 35): G265-G271, 1997. -Sensory stimuli originating from the pharynx inhibit esophageal peristalsis induced by a dry swallow. Our aims were to determine the effect of these stimuli on esopha-geal bolus transport and esophageal peristalsis induced by swallowing difierent volumes of liquid and semisolid boluses. We studied nine healthy volunteers age 35

Objectives/Hypothesis: Deterioration of aerodigestive tract reflexes such as the esophagoglottal and pharyngoglottal closure reflexes and pharyngeal swallow has been documented in the elderly. However, the effect of aging on the contractile response of the upper esophageal sphincter (UES) to pharyngeal water stimulation has not been studied. The aim of this study was to characterize the pharyngo-UES reflex in the healthy elderly. Methods: We studied nine healthy elderly (7761 y[SD]; four men, five women) and nine healthy young volunteers (2662 y[SD]; four men, five women). AUES sleeve sensor was used to measure the pressure. We tested pharyngeal stimulation induced by rapid pulse and slow continuous injection of water. Results: The volume of water required to stimulate the pharyngo-UES contractile reflex by rapid pulse injection in the elderly (0.56 34 0.1mL) was significantly higher than that in the young (0.16 0.02mL) (P<0.05). In contrast to young subjects, there was no pressure increase in resting UES pressure observed in the elderly for continuous pharyngeal water infusion. In both young and elderly, the threshold volume for the pharyngo-UES contractile reflex was significantly lower than that for pharyngeal swallows. Conclusions: The pharyngo-UES contractile reflex deteriorates with aging. This deterioration is primarily due to abnormalities of the afferent limb of the reflex. Key Words: Upper esophageal sphincter, airway protection, pharyngeal stimulation.