Influence of intraluminal acidification on esophageal secondary peristalsis in humans

Esophageal Infusion of Menthol Does Not Affect Esophageal Motility in Patients with Gastroesophageal Reflux Disease

Menthol is thought to trigger gastroesophageal reflux disease (GERD) symptoms by influencing esophageal peristalsis and lower esophageal sphincter (LES) function. We evaluated the effect of esophageal menthol infusion on esophageal motility and the LES in healthy volunteers and in patients with GERD. High resolution manometry (HRM) catheter with attached thin tube for menthol infusion was placed transnasally. Protocol which included baseline recording, 16 water swallows (5 ml, 10 ml, and 15 ml) and the multiple rapid swallows was performed before and after esophageal infusion of menthol (3 mM, 20 min, 8 ml/min). We evaluated the effect of this infusion on the HRM parameters of esophageal peristalsis (distal contractile integral, distal latency, contractile front velocity) and the lower esophageal sphincter (LES) barrier function (integrated relaxation pressure and the inspiratory augmentation of the LES). Simultaneously we evaluated the quality and intensity of the symptoms during the menthol infusion. Esophageal infusion of menthol did not appreciably affect HRM measurements characterizing esophageal peristalsis and LES pressure in healthy subjects (N = 13) or GERD patients (N = 11). The magnitude of the distal contractile integral (5 ml) was changed neither in the healthy volunteers' group, (735 ± 127 vs. 814 ± 117 mmHg, p = 0.5), nor in the GERD patients (295 ± 78 vs. 338 ± 96 mmHg, p = 0.99). In healthy volunteers menthol did not change the inspiratory augmentation of the LES (8.67 ± 1.09 vs. 7.69 ± 0.96 mmHg, p = 0.15) and neither did for GERD patients (8.8 ± 1.18 vs. 8.22 ± 0.91 mmHg, p = 0.43). We observed no significant difference in any HRM parameter following menthol infusion, except for distal latency in 10 ml swallows. By contrast, menthol infusion induced significantly more intense discomfort in GERD patient than in healthy volunteers. Our results suggest no significant temporal effect of menthol on the esophageal motility or LES function, neither in healthy volunteers, nor in GERD. Arguably, other mechanisms are responsible for menthol-related heartburn.

Gastroesophageal reflux disease and chronic cough: A possible mechanism elucidated by ambulatory pH-impedance-pressure monitoring

BACKGROUND

The pathophysiological mechanism(s) of gastroesophageal reflux disease (GERD)-related chronic cough (CC) is unclear. We aimed to determine the mechanism of reflux-induced cough by synchronous monitoring of reflux episodes, esophageal motility, and cough.

METHODS

Patients with GERD were prospectively enrolled and classified into GERD with CC (GERD-CC) and without CC (GERD) groups. Twenty-four-hour ambulatory pH-impedance-pressure monitoring was performed; the reflux patterns, esophageal motility during prolonged exposure to acid and characteristics of reflux episodes that induced coughing paroxysms were analyzed.

KEY RESULTS

Thirty-one patients with GERD-CC and 47 with GERD were enrolled; all of whose monitoring results fulfilled the criteria for diagnosis of GERD. Patients with GERD-CC had higher reflux symptom scores, longer exposure to acid, higher DeMeester scores, and more frequent reflux episodes, proximal extent reflux detected by impedance, and higher percentage of strongly acidic reflux than patients in the GERD group (all P < .05). Of 63 reflux-cough episodes identified in the GERD-CC group, 74.6% of distal reflux and 67.0% of proximal reflux episodes were acidic. More patients had low pan-esophageal pressure in primary peristalsis (48.5% vs 11.8%, P = .000) and synchronous contraction in secondary peristalsis during prolonged exposure to acid in the GERD-CC than in the GERD group (63.9% vs 9.1%, P = .000).

CONCLUSIONS & INFERENCES

Proximal acidic reflux and distal reflux-reflex are jointly associated with reflux-induced cough in patients with GERD. Low pan-esophageal pressure in primary peristalsis and synchronous contraction in secondary peristalsis may play important roles in GERD-associated chronic cough.

Esophageal Motor Dysfunctions in Gastroesophageal Reflux Disease and Therapeutic Perspectives

Gastroesophageal reflux disease (GERD) is a very common disease, and the prevalence in the general population has recently increased. GERD is a chronic relapsing disease associated with motility disorders of the upper gastrointestinal tract. Several factors are implicated in GERD, including hypotensive lower esophageal sphincter, frequent transient lower esophageal sphincter relaxation, esophageal hypersensitivity, reduced resistance of the esophageal mucosa against the refluxed contents, ineffective esophageal motility, abnormal bolus transport, deficits initiating secondary peristalsis, abnormal response to multiple rapid swallowing, and hiatal hernia. One or more of these mechanisms result in the reflux of stomach contents into the esophagus, delayed clearance of the refluxate, and the development of symptoms and/or complications. New techniques, such as 24-hour pH and multichannel intraluminal impedance monitoring, multichannel intraluminal impedance and esophageal manometry, high-resolution manometry, 3-dimensional high-resolution manometry, enoscopic functional luminal imaging probe, and 24-hour dynamic esophageal manometry, provide more information on esophageal motility and have clarified the pathophysiology of GERD. Proton pump inhibitors remain the preferred pharmaceutical option to treat GERD. The ideal target of GERD treatment is to restore esophageal motility and reconstruct the anti-reflux mechanism. This review focuses on current advances in esophageal motor dysfunction in patients with GERD and the influence of these developments on GERD treatment.

Effects of esophageal acid infusion vs mosapride on distension-induced secondary peristalsis in humans

Secondary peristalsis contributes to the clearance of the refluxate from the esophagus. Acute administration of 5-hydroxytryptamine 4 (5-HT₄ ) receptors agonist, mosapride or esophageal infusion of hydrochloric acid (HCl) facilitates secondary peristalsis. The aim of this study was to determine whether esophageal acid infusion and administration of mosapride had different effects on secondary peristalsis. Secondary peristalsis was performed with esophageal distension with rapid and slow air injections in 16 healthy subjects. We performed two separate sessions with HCl (0.1 N) and 40 mg oral mosapride to compare their influence on secondary peristaltic parameters. The threshold volume of secondary peristalsis was significantly lower with HCl infusion than mosapride (P = 0.01) by slow air injections. The threshold volume to generate secondary peristalsis was significantly lower with HCl infusion than mosapride (P = 0.002) by rapid air injections. More secondary peristalsis was trigged by rapid air injections after HCl infusion than mosapride (P = 0.003). Infusion of HCl or mosapride administration has similar effects on peristaltic wave amplitude and duration of primary and secondary peristalsis. Acute esophageal acid infusion can induce greater mechanosensitivity to distension-induced secondary peristalsis than 5-HT₄ receptors agonist mosapride. The data suggest that acid-sensitive afferents are more likely to contribute to sensory modulation of esophageal secondary peristalsis; however, the motility aspects of secondary peristalsis are comparable between acute esophageal acidification and 5-HT₄ receptors activation via mosapride.

Gamma-aminobutyric acid receptor type B agonist baclofen inhibits acid-induced excitation of secondary peristalsis but not heartburn sensation

BACKGROUND AND AIM

Acute esophageal acid infusion promotes distension-induced secondary peristalsis. The gamma-aminobutyric acid receptor type B (GABA-B) receptors activation inhibits secondary peristalsis. This study aimed to test the hypothesis whether acid excitation of secondary peristalsis can be influenced by baclofen.

METHODS

Secondary peristalsis was performed with intra-esophageal slow and rapid air injections in 13 healthy subjects. Direct esophageal infusion of 0.1 N HCl following pretreatment with placebo or baclofen was randomly performed at least 1 week apart. Symptom intensity, distension thresholds, and peristaltic parameters were determined and compared between each study protocol.

RESULTS

The intensity of heartburn symptom in response to esophageal acid infusion was significantly greater with baclofen than the placebo (P = 0.002). The threshold volume of secondary peristalsis during slow air injections in response to acid infusion was significantly greater with baclofen than the placebo (P = 0.001). Baclofen significantly increased the threshold volume of secondary peristalsis during rapid air injections in response to acid infusion (P = 0.001). The frequency of secondary peristalsis in response to acid infusion was significantly decreased by baclofen as compared with the placebo (P = 0.001). Baclofen significantly decreased peristaltic amplitudes in response to acid infusion during rapid air injections (P = 0.007).

CONCLUSIONS

Gamma-aminobutyric acid receptor type B agonist baclofen inhibits acid excitation of secondary peristalsis in human esophagus, which is probably mediated by both muscular and mucosal mechanoreceptors. This work supports the evidence of potential involvement of GABA-B receptors in negative modulation of acid excitation of esophageal perception as well as secondary peristalsis.

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

Objective

Acute 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.

Methods

Secondary 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.

Results

The 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.

Conclusions

Esophageal 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.

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

BACKGROUND/AIM

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.

METHODS

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.

RESULTS

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).

CONCLUSIONS

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.

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

BACKGROUND AND AIM

We aimed to evaluate whether acute esophageal instillation of capsaicin and hydrochloric acid had different effects on distension-induced secondary peristalsis.

METHODS

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).

RESULTS

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.

CONCLUSIONS

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.