Secondary Peristalsis Research Articles

Differences in the Control of Secondary Peristalsis in the Human Esophagus: Influence of the 5-HT4 Receptor versus the TRPV1 Receptor.

ObjectiveAcute administration of 5-hydroxytryptamine4 (5-HT4) receptor agonist, mosapride or esophageal infusion of the transient receptor potential vanilloid receptor-1 (TRPV1) agonist capsaicin promotes secondary peristalsis. We aimed to investigate whether acute esophageal instillation of capsaicin-containing red pepper sauce or administration of mosapride has different effects on the physiological characteristics of secondary peristalsis.MethodsSecondary peristalsis was induced with mid-esophageal air injections in 14 healthy subjects. We compared the effects on secondary peristalsis subsequent to capsaicin-containing red pepper sauce (pure capsaicin, 0.84 mg) or 40 mg oral mosapride.ResultsThe threshold volume for generating secondary peristalsis during slow air distensions was significantly decreased with capsaicin infusion compared to mosapride (11.6 ± 1.0 vs. 14.1 ± 0.8 mL, P = 0.02). The threshold volume required to produce secondary peristalsis during rapid air distension was also significantly decreased with capsaicin infusion (4.6 ± 0.5 vs. 5.2 ± 0.6 mL, P = 0.02). Secondary peristalsis was noted more frequently in response to rapid air distension after capsaicin infusion than mosapride (80% [60–100%] vs. 65% [5–100%], P = 0.04). Infusion of capsaicin or mosapride administration didn’t change any parameters of primary or secondary peristalsis.ConclusionsEsophageal infusion with capsaicin-containing red pepper sauce suspension does create greater mechanosensitivity as measured by secondary peristalsis than 5-HT4 receptor agonist mosapride. Capsaicin-sensitive afferents appear to be more involved in the sensory modulation of distension-induced secondary peristalsis.

Sa1324 Effects of Prucalopride on Esophageal Secondary Peristalsis in Humans

Sa1324 Effects of Prucalopride on Esophageal Secondary Peristalsis in Humans

Effects of esophageal capsaicin instillation on acid induced excitation of secondary peristalsis in humans.

Esophageal instillation of capsaicin or hydrochloric acid enhances secondary peristalsis. Our aim was to investigate whether intra-esophageal capsaicin infusion can influence symptom perception and physiological alteration of secondary peristalsis subsequent to acid infusion. Secondary peristalsis was induced by mid-esophagus injections of air in 18 healthy subjects. Two different sessions including esophageal infusion of hydrochloric acid (0.1 N) following pretreatment with saline or capsaicin-containing red pepper sauce were randomly performed at least one week apart. Symptoms of heartburn and secondary peristalsis were determined and compared between each study session. The intensity of heartburn symptom subsequent to acid infusion was significantly reduced after capsaicin infusion as compared with saline infusion (54 ± 3 vs 61 ± 3; P = 0.03). Capsaicin infusion significantly increased the threshold volume of secondary peristalsis to rapid air injections subsequent to esophageal acid infusion (8.0 ± 0.5 mL vs 4.4 ± 0.3 mL; P < 0.0001). The frequency of secondary peristalsis subsequent to acid infusion was significantly decreased after capsaicin infusion as compared to saline infusion (70% [60-82.5%] vs 80% [70-90%]; P = 0.03). Capsaicin infusion significantly decreased the pressure wave amplitude of secondary peristalsis subsequent to acid infusion during rapid air injections (90.6 ± 8.7 mmHg vs 111.1 ± 11.1 mmHg; P = 0.03). Capsaicin appears to desensitize the esophagus to acid induced excitation of secondary peristalsis in humans, which is probably mediated by rapidly adapting mucosal mechanoreceptors. High capsaicin-containing diet might attenuate normal physiological response to abrupt acid reflux by inhibiting secondary peristalsis.

Influence of capsaicin infusion on secondary peristalsis in patients with gastroesophageal reflux disease

AIMTo determine whether capsaicin infusion could influence heartburn perception and secondary peristalsis in patients with gastroesophageal reflux disease (GERD).METHODSSecondary peristalsis was performed with slow and rapid mid-esophageal injections of air in 10 patients with GERD. In a first protocol, saline and capsaicin-containing red pepper sauce infusions were randomly performed, whereas 2 consecutive sessions of capsaicin-containing red pepper sauce infusions were performed in a second protocol. Tested solutions including 5 mL of red pepper sauce diluted with 15 mL of saline and 20 mL of 0.9% saline were infused into the mid-esophagus via the manometric catheter at a rate of 10 mL/min with a randomized and double-blind fashion. During each study protocol, perception of heartburn, threshold volumes and peristaltic parameters for secondary peristalsis were analyzed and compared between different stimuli.RESULTSInfusion of capsaicin significantly increased heartburn perception in patients with GERD (P < 0.001), whereas repeated capsaicin infusion significantly reduced heartburn perception (P = 0.003). Acute capsaicin infusion decreased threshold volume of secondary peristalsis (P = 0.001) and increased its frequency (P = 0.01) during rapid air injection. The prevalence of GERD patients with successive secondary peristalsis during slow air injection significantly increased after capsaicin infusion (P = 0.001). Repeated capsaicin infusion increased threshold volume of secondary peristalsis (P = 0.002) and reduced the frequency of secondary peristalsis (P = 0.02) during rapid air injection.CONCLUSIONAcute esophageal exposure to capsaicin enhances heartburn sensation and promotes secondary peristalsis in gastroesophageal reflux disease, but repetitive capsaicin infusion reverses these effects.

Secondary Esophageal Peristalsis in Patients With GERD

Introduction: We have reported that the triggering of secondary peristalsis is defective in patients with NERD but the difference in the triggering of secondary peristalsis between patients with NERD and patients with RE is poorly understood, therefore the aim of this study is to evaluate the difference in esophageal motility between patients with NERD and RE. Methods: 20 patients with NERD, who also had gastroesophageal reflux symptoms which occurred more than twice per week, were compared with 20 patients with mild RE of LA-grade A or B, 20 patients with severe RE of LA-grade C and 20 healthy subjects (HS). Manometry was carried out with a perfused assembly, which incorporated side holes in the pharynx, the UES, the esophagus, and 10 side holes (1cm apart), which straddled the distal esophagus, the esophagogastric junction and the proximal stomach. An infusion port, located 18cm above the distal side hole, was used to inject air. Secondary peristalsis was triggered by esophageal distention, using a 20ml bolus of air, injected rapidly, by hand, into the middle esophagus. After 20 seconds each stimulus was followed by a dry swallow to clear any residual air and then each stimulus was repeated 5 times. Results: The success rate of secondary peristalsis in patients with severe RE (20 % (0.0-40.0)) was significantly lower than in patients with mild RE (40.0 (20.0-80.0)) and HS (80.0 (70.0-90.0)) but there was no difference in the success rate of secondary peristalsis between patients with severe RE and patients with NERD (20 (0.0-40.0)). The success rate of secondary peristalsis in patients with mild RE was significantly lower than that of HS, but was significantly higher than that of patients with NERD. The success rate of secondary peristalsis in patients with NERD was significantly lower than that of HS. The amplitude of secondary peristalsis in patients with severe RE (25.0 mmHg (14.0-40.0)) was significantly lower than in patients with mild RE (41.0 (27.0-60.0)), patients with NERD (52.5 (40.0-70.0)) and HS (46.0 (33.0-63.0)). The amplitude of secondary peristalsis in patients with mild RE was significantly lower than that of NERD. Conclusion: Defective secondary peristalsis was observed in patients with NERD and those with RE and the success rate of secondary peristalsis significantly decreased in accordance with the severity of RE. The degree of defective secondary peristalsis in patients with NERD was similar to that of patients with severe RE.

Effects of Aging and Acid Reflux on Esophageal Motility

Introduction: It is generally thought that esophageal motility decreases with age, however a decrease in esophageal motility may also be caused by esophagitis. The aim of this study is to investigate the effects of aging and acid reflux on esophageal motility. Methods: 40 young (under 45) healthy subjects (HS) and 40 elderly (over 65) HS, with neither reflux symptoms nor reflux esophagitis (RE), and 40 elderly patients with mild RE (elderly RE), underwent esophageal high resolution manometry with a 21-lumen perfused assembly, which monitored pressure in the pharynx, the upper esophageal sphincter, the esophageal body, the lower esophageal sphincter (LES) and the proximal stomach. An infusion port, located 18cm above the distal side hole, was used to inject air and expiratory basal LES pressure was referenced to end expiratory intragastric pressure. Primary peristalsis was tested with 5ml water swallows, each swallow separated by a 30 second interval and the process repeated 10 times. Secondary peristalsis was triggered by esophageal distention, using a 20ml bolus of air, which was injected rapidly, by hand, into the middle esophagus. After 20 seconds each stimulus was followed by a dry swallow to clear any of the residual air and then repeated 5 times. Results: There was no difference in the LES pressure and also in the success rate of primary peristalsis between young and elderly HS or between elderly HS and RE. There was no difference in the distal contractile integral (DCI) of primary peristalsis and secondary peristalsis between the young and elderly HS, but in the elderly RE, it was significantly lower than in the elderly HS. There was no difference in the success rate of secondary peristalsis between elderly HS and RE, but in elderly HS it was significantly lower than in young HS. Conclusion: Aging may cause a decrease in the success rate of secondary peristalsis, and acid reflux itself may cause a decrease of the DCI in primary and secondary peristalsis.

Mechanisms of cough provocation and cough resolution in neonates with bronchopulmonary dysplasia.

Cough and deglutition are protective mechanisms that defend against aspiration. We identified mechanisms associated with cough provocation as well as those associated with cough resolution in infants with bronchopulmonary dysplasia (BPD). Manometry signatures of cough were recognized in 16 premature infants with BPD undergoing concurrent esophageal manometry, respiratory inductance plethysmography, and nasal air flow measurements. Pretussive and post-tussive pharyngo-esophageal motility changes were analyzed. Mechanisms associated with cough and mechanisms that restored respiratory and esophageal normalcy were analyzed. We analyzed 312 cough events during 88 cough clusters; 97% were associated with recognizable manometric patterns. Initial mechanisms related with coughing included nonpropagating swallow (59%), upper esophageal sphincter (UES) reflex contraction (18%), and lower esophageal sphincter (LES) relaxation (14%). UES and LES dysfunction was present in 69% of nonpropagating swallow-associated cough clusters. Mechanisms restoring post-tussive normalcy included primary peristalsis (84%), secondary peristalsis (8%), and none recognized (8%). UES contraction reflex was associated with cough clusters more frequently in infants on nasal continuous positive airway pressure (NCPAP) (OR = 9.13, 95% CI = 1.88-44.24). Cough clusters in infants with BPD had identifiable etiologies associated with esophageal events; common initial mechanisms were of upper aerodigestive origin, while common clearing mechanisms were peristaltic reflexes.

Utilizing functional lumen imaging probe topography to evaluate esophageal contractility during volumetric distention: a pilot study.

The functional lumen imaging probe (FLIP) measures luminal cross-sectional area and pressure during volumetric distension. By applying novel customized software to produce FLIP topography plots, organized esophageal contractility can be visualized and analyzed. We aimed to describe the stimulus thresholds and contractile characteristics for distension-induced esophageal body contractility using FLIP topography in normal controls. Ten healthy controls were evaluated during endoscopy with FLIP. During stepwise bag distension, simultaneous intra-bag pressure and luminal diameter measurements were obtained and exported to a MatLab program to generate FLIP topography plots. The distension volume, intra-bag pressure, and maximum esophageal body diameters were measured for the onset and cessation of repetitive antegrade contractions (RACs). Contraction duration, interval, magnitude, and velocity were measured at 8 and 3-cm proximal to the esophagogastric junction. Eight of ten subjects demonstrated RACs at a median onset volume of 29 mL (IQR: 25-38.8), median intra-bag pressure of 10.7 mmHg (IQR: 8.6-15.9), and median maximum esophageal body diameter of 18.5 mm (IQR: 17.5-19.6). Cessation of RACs occurred prior to completion of the distension protocol in three of the eight subjects exhibiting RACs. Values of the RAC-associated contractile metrics were also generated to characterize these events. Distension-induced esophageal contractions can be assessed utilizing FLIP topography. RACs are a common finding in asymptomatic controls in response to volume distention and have similar characteristics to secondary peristalsis and repetitive rapid swallows.

Tu1426 Differences in the Control of Distension-Induced Secondary Peristalsis in Human Esophagus: the Role of 5-HT4 Receptor Versus TRPV1 Receptor

Tu1426 Differences in the Control of Distension-Induced Secondary Peristalsis in Human Esophagus: the Role of 5-HT4 Receptor Versus TRPV1 Receptor

Tu1145 Effects of Esophageal Capsaicin Instillation on Acid Induced Excitation of Secondary Peristalsis in Humans

Tu1145 Effects of Esophageal Capsaicin Instillation on Acid Induced Excitation of Secondary Peristalsis in Humans

Effects of Aging and Acid Reflux on Esophageal Motility

Backgrounds: It is generally thought that esophageal motility decreases with age; however, a decrease in esophageal motility may also be caused by esophagitis. The aim of this study is to investigate the effects of aging and acid reflux on esophageal motility. Methods: 40 young (under 45) healthy subjects (HS), 40 elderly (over 65) HS, and 40 elderly (over 65) patients with mild reflux esophagitis (RE), underwent esophageal high-resolution manometry (HRM). Lower esophageal sphincter pressure (LESP), primary peristalsis (PP), and secondary peristalsis (SP) were evaluated. Results: There was no difference in the LESP and also in the success rate of PP between young and elderly HS or between elderly HS and RE. There was no difference in the distal contractile integral (DCI) of PP and SP between the young and elderly HS, but in the elderly RE, it was significantly lower than in the elderly HS. There was no difference in the success rate of SP between elderly HS and RE, but in elderly HS it was significantly lower than in young HS. Conclusions: Aging may cause a decrease in the success rate of SP, and acid reflux itself may cause a decrease of the DCI in PP and SP.

Influence of repeated infusion of capsaicin-contained red pepper sauce on esophageal secondary peristalsis in humans.

The transient receptor potential vanilloid 1 has been implicated as a target mediator for heartburn perception and modulation of esophageal secondary peristalsis. Our aim was to determine the effect of repeated esophageal infusion of capsaicin-contained red pepper sauce on heartburn perception and secondary peristalsis in healthy adults. Secondary peristalsis was performed with mid-esophageal injections of air in 15 healthy adults. Two separate protocols including esophageal infusion with saline and capsaicin-contained red pepper sauce and 2 consecutive sessions of capsaicin-contained red pepper sauce were randomly performed. After repeated infusion of capsaicin-contained red pepper sauce, the threshold volume to activate secondary peristalsis was significantly increased during slow (p<0.001) and rapid air injections (p=0.004). Acute infusion of capsaicin-contained red pepper sauce enhanced heartburn perception (p<0.001), but the intensity of heartburn perception was significantly reduced after repeated capsaicin-contained red pepper sauce infusion (p=0.007). Acute infusion of capsaicin-contained red pepper sauce significantly increased pressure wave amplitudes of distal esophagus during slow (p=0.003) and rapid air injections (p=0.01), but repeated infusion of capsaicin-contained red pepper sauce significantly decreased pressure wave amplitude of distal esophagus during slow (p=0.0005) and rapid air injections (p=0.003). Repeated esophageal infusion of capsaicin appears to attenuate heartburn perception and inhibit distension-induced secondary peristalsis in healthy adults. These results suggest capsaicin-sensitive afferents in modulating sensorimotor function of secondary peristalsis in human esophagus.

Tu1971 Circular & Longitudinal Muscles Slide Against Each Other in Opposite Directions During Peristalsis & Transient Lower Esophageal Sphincter Relaxation

planimetry data from each subject were exported to MATLABTM (The Math Works, Natick, MA). A customized MATLAB program generated a plot (Figure) that included distension volume (bottom panel), 16 channels of diameter changes (middle panel) and intrabag pressure (top panel) over whole study period. The start of reactivity defined by nonpropagating or intermittent contractions and the onset of continuous secondary peristalsis were identified by noting periods of reduced diameter as a surrogate for contraction. The pressure and volume at the onset of these events were measured and compared using nonparametric tests. Results: All healthy subjects had evidence of reactivity and 8 of 10 had secondary peristaltic contractions either lasting to the maximal distension volume (60 ml in 6 subjects) or stopping earlier (35-45 ml in 2 subjects). Thirteen EoE patients had reactivity, but only 7 had secondary peristaltic contractions, few than healthy controls but not reaching statistical significance (see Table). The threshold intrabag pressure values associated with onset of reactivity and onset of secondary peristaltic contractions were significantly higher in the EoE group compared with healthy controls (see Table). The intrabag volumes at onset of reactivity and onset of continuous contractions were also significantly higher in the EoE group (see Table). Conclusions: Patients with EoE require higher intra-esophageal pressures to generate esophageal reactivity and secondary peristalsis when compared with healthy controls. Of the EoE patients who develop reactivity with balloon distention, significantly fewer went on to develop evidence of secondary peristalsis than healthy controls.Whether this difference is associated with known clinical complications of EoE such as food impaction or GERD requires further study.

Esophageal reflexes modulate frontoparietal response in neonates: Novel application of concurrent NIRS and provocative esophageal manometry.

Central and peripheral neural regulation of swallowing and aerodigestive reflexes is unclear in human neonates. Functional near infrared spectroscopy (NIRS) is a noninvasive method to measure changes in oxyhemoglobin (HbO) and deoxyhemoglobin (HbD). Pharyngoesophageal manometry permits evaluation of aerodigestive reflexes. Modalities were combined to investigate feasibility and to test neonatal frontoparietal cortical changes during pharyngoesophageal (visceral) stimulation and/or swallowing. Ten neonates (45.6 ± 3.0 wk postmenstrual age, 4.1 ± 0.5 kg) underwent novel pharyngoesophageal manometry concurrent with NIRS. To examine esophagus-brain interactions, we analyzed cortical hemodynamic response (HDR) latency and durations during aerodigestive provocation and esophageal reflexes. Data are presented as means ± SE or percent. HDR rates were 8.84 times more likely with basal spontaneous deglutition compared with sham stimuli (P = 0.004). Of 182 visceral stimuli, 95% were analyzable for esophageal responses, 38% for HDR, and 36% for both. Of analyzable HDR (n = 70): 1) HbO concentration (μmol/l) baseline 1.5 ± 0.7 vs. 3.7 ± 0.7 poststimulus was significant (P = 0.02), 2) HbD concentration (μmol/l) between baseline 0.1 ± 0.4 vs. poststimulus -0.5 ± 0.4 was not significant (P = 0.73), and 3) hemispheric lateralization was 21% left only, 29% right only, and 50% bilateral. During concurrent esophageal and NIRS responses (n = 66): 1) peristaltic reflexes were present in 74% and HDR in 61% and 2) HDR was 4.75 times more likely with deglutition reflex vs. secondary peristaltic reflex (P = 0.016). Concurrent NIRS with visceral stimulation is feasible in neonates, and frontoparietal cortical activation is recognized. Deglutition contrasting with secondary peristalsis is related to cortical activation, thus implicating higher hierarchical aerodigestive protective functional neural networks.

Mo1875 Effect of Repeated Esophageal Infusion of Capsaicin-Contained Red Pepper Sauce on Secondary Peristalsis in Humans

Mo1875 Effect of Repeated Esophageal Infusion of Capsaicin-Contained Red Pepper Sauce on Secondary Peristalsis in Humans

Quantitative Differences Between Primary and Secondary Peristaltic Contractions of the Esophagus

Differences in contraction characteristics between primary and secondary peristalsis have only been scarcely studied. Recently new measures of contractile activity in the human esophagus were developed. The study aims were to use combined manometry and impedance planimetry [pressure-cross-sectional area (P-CSA)] recordings from healthy volunteers to examine esophageal peristalsis, and, furthermore, to investigate the effect of the motility enhancing drug erythromycin to study differential effects on the two types of contractions. Sixteen healthy volunteers participated in the study [mean age 23 (range, 19-34) years, 6 females]. An esophageal probe with a bag for CSA measurement was positioned 10 cm above the lower esophageal sphincter. Bag volume was increased stepwise from 5 to 25 ml before and after intravenous infusion of 250 mg erythromycin. Swallow-evoked primary and distension-evoked secondary esophageal peristalsis were compared with regard to (1) pressure amplitude, (2) CSA amplitude, (3) preload tension (wall tension before an evoked contraction), (4) contractile tension, and (5) work outputs. Primary peristalsis induced more efficient contractions as the contraction amplitudes, work output and contractile tension were higher compared to secondary peristalsis (P < 0.001). Erythromycin induced change in CSA during distension-evoked secondary peristalsis (CSA before 212.9 ± 26.8 vs. after 180.5 ± 23.3, P < 0.05). The sensitivity to esophageal distension increased with the distending volume both before and during erythromycin. The sensitivity was not changed by erythromycin (P = 0.6). Esophageal primary peristaltic contractions were more forceful with longer duration, and higher work output compared to secondary peristalsis contractions. Erythromycin affected peristalsis only to a minor degree.

Relevance of ineffective esophageal motility to secondary peristalsis in patients with gastroesophageal reflux disease

The study aimed to investigate the hypothesis whether the presence of Ineffective esophageal motility would affect physiological characteristics of secondary peristalsis. Secondary peristalsis was performed with slow and rapid air injections into mid-esophagus of 18 ineffective esophageal motility patients and 15 age-matched controls. Severity of ineffective esophageal motility was defined by the application of combined multichannel intraluminal impedance and manometry. Ineffective esophageal motility patients included 11 patients without impedance abnormality and seven patients with impedance abnormality during liquid and/or viscous swallowing. The prevalence of failed secondary peristaltic response during slow air injection was significantly greater in ineffective esophageal motility patients without impedance abnormality (3/11 [27%], P < 0.001) and with impedance abnormality (4/7 [57%], P = 0.04) than healthy subjects. The threshold volume for inducing secondary peristalsis during rapid air injection was significantly greater in ineffective esophageal motility patients with impedance abnormality (6.1 ± 0.3 mL) than healthy subjects (4.6 ± 0.3 mL, P < 0.05) and ineffective esophageal motility patients without impedance abnormality (4.1 ± 0.4 mL, P < 0.05). The frequency of peristaltic response during rapid air injection was significantly lower in ineffective esophageal motility patients with impedance abnormality (40% [20-50%] than healthy subjects (90% [90-100%], P < 0.05). Defective activation of secondary peristalsis is present in ineffective esophageal motility patients with impedance abnormality. Our study indicates that increased ineffective esophageal motility severity associated with defective triggering of secondary peristalsis may contribute to impaired esophageal clearance in patients with gastroesophageal reflux disease.

Impairment of secondary peristalsis in Barrett’s esophagus by transnasal endoscopy-based testing

To investigate dysfunctions in esophageal peristalsis and sensation in patients with Barrett's esophagus following acid infusion using endoscopy-based testing. First, physiological saline was infused into the esophagus of five healthy subjects, at a rate of 10 mL/min for 10 min, followed by infusion of HCl. Esophageal contractions were analyzed to determine whether the contractions observed by endoscopy and ultrasonography corresponded to the esophageal peristaltic waves diagnosed by manometry. Next, using nasal endoscopy, esophageal sensations and contractions were investigated in patients with, as well as controls without, Barrett's esophagus using the same infusion protocol. All except one of the propulsive contractions identified endoscopically were recorded as secondary peristaltic waves by manometry. Patients with long segment Barrett's esophagus (LSBE) tended to have a shorter lag time than the control group, although the difference did not reach statistical significance (88 ± 54 s vs 162 ± 150 s respectively, P = 0.14). Furthermore, patients with LSBE had significantly fewer secondary contractions following the infusion of both saline and HCl than did either the control group or patients with short segment Barrett's esophagus (4.1 ± 1.2 vs 8.0 ± 2.8, P < 0.001 and 7.3 ± 3.2, P < 0.01, respectively, following saline infusion; 5.3 ± 1.2 vs 8.4 ± 2.4 and 8.1 ± 2.9 respectively, P < 0.01 for both, following infusion of HCl). Using nasal endoscopy and a simple acid-perfusion study, we were able to demonstrate disorders in secondary peristalsis in patients with LSBE.

CPG-based control of a swallowing robot

CPGs are non-linear oscillators formed by neural circuits which can generate rhythmic movements without receiving central input or rhythmic sensory feedback. They are the essential mechanism under animal rhythmic locomotion. In this paper, a biological inspired CPG controller was adopted to control a swallowing robot based on a recurrent cyclic inhibition (RCI) circuit. In this design, the RCI consist of three neurons generate rhythmic movement. There are two kinds of working method under this control system in order to mimic human swallowing process: one is to modelling the behaviour the primary peristalsis, and the other is to imitating the secondary peristalsis.

Comparable effects of capsaicin‐containing red pepper sauce and hydrochloric acid on secondary peristalsis in humans

We aimed to evaluate whether acute esophageal instillation of capsaicin and hydrochloric acid had different effects on distension-induced secondary peristalsis. Secondary peristalsis was induced by slow and rapid air injections into the mid-esophagus after the evaluation of baseline motility in 16 healthy subjects. The effects on secondary peristalsis were determined by esophageal instillation with capsaicin-containing red pepper sauce (pure capsaicin, 0.84 mg) and hydrochloric acid (0.1 N). The administration of capsaicin induced a significant increase in the visual analogue scale score for heartburn as compared with hydrochloric acid (P = 0.002). The threshold volume for generating secondary peristalsis during slow and rapid air distensions did not differ between capsaicin and hydrochloric acid infusions. Hydrochloric acid significantly increased the frequency of secondary peristalsis in response to rapid air distension compared with capsaicin infusion (P = 0.03). Pressure wave amplitude during slow air distension was greater with the infusion of hydrochloric acid than capsaicin infusion (P = 0.001). The pressure wave duration during rapid air distension was longer after capsaicin infusion than hydrochloric acid infusion (P = 0.01). The pressure wave amplitude during rapid air distension was similar between capsaicin and hydrochloric acid infusions. Despite subtle differences in physiological characteristics of secondary peristalsis, acute esophageal instillation of capsaicin and hydrochloric acid produced comparable effects on distension-induced secondary peristalsis. Our data suggest the coexistence of both acid- and capsaicin-sensitive afferents in human esophagus which produce similar physiological alterations in secondary peristalsis.