Inhibitory beta adrenergic receptors in the human distal esophagus

Gastroesophageal Reflux Disease Is Not Associated With Jackhammer Esophagus: A Case-control Study

Background/Aims

The pathophysiology of jackhammer esophagus (JE) remains unknown but may be related to gastroesophageal reflux disease or medication use. We aim to determine if pathologic acid exposure or the use of specific classes of medications (based on the mechanism of action) is associated with JE.

Methods

High-resolution manometry (HRM) studies from November 2013 to March 2019 with a diagnosis of JE were identified and compared to symptomatic control patients with normal HRM. Esophageal acid exposure and medication use were compared between groups. Multivariate regression analysis was performed to look for predictors of mean distal contractile integral.

Results

Forty-two JE and 127 control patients were included in the study. Twenty-two (52%) JE and 82 (65%) control patients underwent both HRM and ambulatory pH monitoring. Two (9%) JE patients and 14 (17%) of controls had evidence of abnormal acid exposure (DeMeester score > 14.7); this difference was not significant (P = 0.290). Thirty-six (86%) JE and 127 (100%) control patients had complete medication lists. Significantly more JE patients were on long-acting beta agonists (LABA) (JE = 5, control = 4; P = 0.026) and calcium channel blockers (CCB) (JE = 5, control = 3; P = 0.014). Regular opioids (β = 0.298, P = 0.042), CCB (β = 0.308, P = 0.035), and inhaled anticholinergics (β = 0.361, P = 0.049) predicted mean distal contractile integral (R² = 0.082, F = 4.8; P = 0.003).

Conclusions

Pathologic acid exposure does not appear to be associated with JE. JE patients had increased CCB and LABA use. The unexpected finding of increased LABA use warrants more investigation and may provide support for a cholinergic etiology of JE.

Causal contributions of human frontal eye fields to distinct aspects of decision formation

Several theories propose that perceptual decision making depends on the gradual accumulation of information that provides evidence in favour of one of the choice-options. The outcome of this temporally extended integration process is thought to be categorized into the 'winning' and 'losing' choice-options for action. Neural correlates of corresponding decision formation processes have been observed in various frontal and parietal brain areas, among them the frontal eye-fields (FEF). However, the specific functional role of the FEFs is debated. Recent studies in humans and rodents provide conflicting accounts, proposing that the FEF either accumulate the choice-relevant information or categorize the outcome of such evidence integration into discrete actions. Here, we used transcranial magnetic stimulation (TMS) on humans to interfere with either left or right FEF activity during different timepoints of perceptual decision-formation. Stimulation of either FEF affected performance only when delivered during information integration but not during subsequent categorical choice. However, the patterns of behavioural changes suggest that the left-FEF contributes to general evidence integration, whereas right-FEF may direct spatial attention to the contralateral hemifield. Taken together, our results indicate an FEF involvement in evidence accumulation but not categorization, and suggest hemispheric lateralization for this function in the human brain.

Intrathoracic airway obstruction and gastroesophageal reflux: a canine model

INTRODUCTION

Gastroesophageal reflux (GER) is common in children with airway disorders. Previous studies have shown an association between upper airway obstruction and GER in experimental animal models. However, the cause and effect relationship between intrathoracic airway obstruction (IAO) and GER is obscure. The goal of this study is to investigate the association between IAO and GER using the canine model.

METHODS

In sedated dogs, a telemetric implant was placed subcutaneously (with one pressure sensor tip each in intrapleural space and abdomen) to monitor intrapleural pressure (IPP) and intrabdominal pressure (IAP). The IPP and the IAP were monitored intraoperatively and in conscious dogs on the 7th to 10th postoperative days. GER was assessed by determining the reflux index (RI), based on the intraesophageal pH recording performed continuously for a 24 hr period using a pH probe. After 2-3 weeks following placement of the telemetric implant, IAO was surgically created in the dog. After maintaining IAO for 2 weeks, the IPP, IAP, and pH measurements were monitored again following the same protocol as before IAO.

RESULTS

After the creation of IAO, there was no significant change observed in the mean RI either in the distal (P = 0.716) or proximal (P = 0.962) esophageal lumens. The IPP became significantly more negative (P = 0.006) and the IAP turned significantly negative (P < 0.001) from being positive compared to the respective values before IAO. However, transdiaphragmatic pressure (Pdi) did not change significantly (P = 0.08).

CONCLUSION

We conclude that moderate IAO does not cause GER in our animal model. It can be explained by the absence of significant change in Pdi after creation of IAO.

Convulsions and possible spasm of the lower oesophageal sphincter in a fatal case of propranolol intoxication

A fatal case of propranolol intoxication is described. The patient had ingested 3-5 g of the drug and probably no other drugs. Gastric lavage could not be performed due to some kind of obstruction in the distal part of the oesophagus. At autopsy, the oesophagus was normal, and a spasm due to B-blockade is suggested. Epileptiform seizures resistant to treatment with diazepam and barbiturates were frequent and probably not solely caused by cerebral ischaemia.

Mechanisms of gastroesophageal reflux in critically ill mechanically ventilated patients

BACKGROUND & AIMS

Gastroesophageal reflux is a major problem in mechanically ventilated patients and may lead to pulmonary aspiration and erosive esophagitis. Transient lower esophageal sphincter relaxations are the most common mechanism underlying reflux in nonventilated patients. The mechanisms that underlie reflux in critically ill ventilated patients have not been studied. The aim of this study was to determine the mechanisms underlying gastroesophageal reflux in mechanically ventilated patients in the intensive care unit.

METHODS

In 15 mechanically ventilated intensive care unit patients, esophageal motility, pH, and intraluminal impedance (11/15 patients) were recorded for 1 hour before and 5 hours during continuous nasogastric feeding.

RESULTS

Basal lower esophageal sphincter pressure was uniformly low (2.2 +/- 0.4 mmHg). The median (interquartile range) acid exposure (pH <4) was 39.4% (0%-100%) fasting and 32% (7.5%-94.2%) fed. Acid reflux occurred in 10 patients, but slow drifts in esophageal pH were also an important contributor to acid exposure. If esophageal pH decreased to pH <4, it tended to remain so for prolonged periods. A total of 46 acid reflux events were identified. Most (55%) occurred because of absent lower esophageal sphincter pressure alone; 45% occurred during straining or coughing.

CONCLUSIONS

Gastroesophageal reflux in mechanically ventilated patients is predominantly due to very low or absent lower esophageal sphincter pressure, often with a superimposed cough or strain. These data suggest that measures that increase basal LES pressure may be useful to prevent reflux in ventilated patients.

The association of gastroesophageal reflux disease with asthma and chronic cough in the adult

Gastroesophageal reflux disease (GERD) is a common condition which is particularly prevalent in patients with asthma and chronic cough. Physiologic changes caused by asthma and chronic cough promote acid reflux. GERD is also considered by many investigators as a factor contributing to airway inflammation. An etiological relationship between GERD and asthma/chronic cough and vice versa has been supported by a large number of experimental and clinical findings and refuted by others. Although further controlled studies are needed to clarify this relationship, GERD and asthma/chronic cough appear to be linked to each other. The association of GERD with asthma and chronic cough involves nerve reflexes, cytokines, inflammatory and neuroendocrine cells and, in some patients, tracheal aspiration of refluxing gastric fluids. GERD may present with typical symptoms but can also be asymptomatic. Sensitive methods for diagnosing GERD are available, which include esophageal pH monitoring, acid provocative tests, modified barium swallow and endoscopy. Consideration of the association of GERD with asthma and chronic cough is of practical value in the management of chronic cough or asthma resistant to treatment. Treatment of GERD in patients with asthma has been consistently shown to improve respiratory symptoms but not necessarily pulmonary function tests. Surgical treatment can be a useful and cost-effective approach in selected patients with asthma and GERD.

Clinical implications of gastroesophageal reflux disease and swallowing dysfunction in COPD

The intimate anatomical and physiologic relationship between the upper airway and esophagus consists of complex interactions between various muscles and nerves with both voluntary and involuntary patterns of control. Alterations in this harmonic relationship can lead to swallowing abnormalities ranging from dysphagia to gross aspiration, gastroesophageal reflux disease (GERD) and chronic cough. There is a paucity of data regarding pathologic alterations in the upper airway-esophageal relationship in patients with COPD. The association between GERD and respiratory symptoms is well recognized in the setting of asthma; however, the nature of this relationship remains controversial. The association of GERD and COPD is even less clear. A review of the limited data on GERD and swallowing abnormalities in patients with COPD indicate that prevalence of GERD and esophageal disorders in patients with COPD is higher than in the normal population. However, its contribution to respiratory symptoms, bronchodilator use and pulmonary function in patients with COPD remains unknown. Although dysphagia and swallowing dysfunction on videofluoroscopic swallow evaluation are common in patients with COPD, their role as exacerbators of COPD remains to be elucidated. Further clinical research is necessary to evaluate the role of GERD and swallowing dysfunction in both stable and acute exacerbation of COPD.

Gastroesophageal reflux and asthma: are they related?

The relationship between asthma and gastroesophageal reflux (GER) is controversial. This paper reviews the evidence for an association between them, the effect of asthma on GER, and the effects of GER and antireflux therapy on asthma. The association between the two conditions seems firm but studies of the effects of GER on asthma and asthma on GER are contradictory. Critical review suggests that GER affects asthma symptoms but not pulmonary function. Antireflux therapy improves asthma symptoms and reduces medication requirements but does not improve pulmonary function. The paradox of GER causing asthma symptoms but not changing pulmonary function may be explained by its increasing minute ventilation rather than triggering bronchospasm.

Gastroesophageal reflux and asthma: a review of pathogenesis, diagnosis, and therapy

Gastroesophageal reflux disease (GERD) occurs in up to one-third of the adult US population. Most affected individuals are either unaware of their condition or do not seek medical help, relying on nonprescription acid suppressants and antacids for relief. GERD, a common disorder of infancy, old age, and pregnancy, is particularly prevalent in patients with asthma. A causal relationship between the two diseases has been postulated by many investigators. The physiologic changes of asthma exacerbations and the actions of some of the medications used to treat asthma both aggravate GERD. The adverse effect of GERD on asthma and the pathophysiology of this relationship are still under debate. Some studies showed no objective improvement by spirometry of asthmatics treated for GERD, but recognized improvement in asthma symptoms and decreased use of asthma medication. Other studies, supporting GERD induction of asthma, have been performed to test two hypotheses: that asthma is exacerbated by endotracheal aspiration of gastric contents or by a reflex response to stimulation of esophageal receptors. Clinical experience has shown that early diagnosis and treatment of GERD often leads to better control of asthma.

Functional gut disorders: from motility to sensitivity disorders. A review of current and investigational drugs for their management

Functional gut disorders include several clinical entities defined on the basis of symptom patterns (e.g., functional dyspepsia, irritable bowel syndrome, functional abdominal pain, functional abdominal bloating), for which there is no established pathophysiological mechanism. Because there is no well-defined pathophysiological target, treatment should be aimed at symptom improvement. Prokinetics and antispasmodics have been widely used in the treatment of functional gut disorders on the assumption that disordered motility is the underlying cause of symptoms, and symptom improvement is indeed achievable with these compounds in some, but not all, patients with features of hypo- or hypermotility, respectively. In the first part of this review, we cover the basic pharmacology and discuss the rationale for the clinical use of prokinetics and antispasmodics. On the other hand, in the past few years, the explosive growth in the research focusing on visceral sensitivity and visceral reflexes has suggested that at least some patients with functional gut disorders have altered visceral perception. Thus, the second part of the review covers these developments and focuses on studies addressing the issue of drugs modulating visceral sensitivity.

Adrenergic mechanisms in the control of gastrointestinal motility: from basic science to clinical applications

Over the years, a vast literature has accumulated on the adrenergic mechanisms controlling gut motility, blood flow, and mucosal transport. The present review is intended as a survey of key information on the relevance of adrenergic mechanisms modulating gut motility and will provide an outline of our knowledge on the distribution and functional role of adrenoceptor subtypes mediating motor responses. alpha1-Adrenoceptors are located postsynaptically on smooth muscle cells and, to a lesser extent, on intrinsic neurons; alpha2-adrenoceptors may be present both pre- and postsynaptically, with presynaptic auto- and hetero-receptors playing an important role in the modulation of neurotransmitter release; beta-adrenoceptors are found mainly on smooth muscle cells. From a clinical standpoint, adrenoceptor agonists/antagonists have been investigated as potential motility inhibiting (antidiarrheal/antispasmodic) or prokinetic agents, although at present their field of application is limited to select patient groups.

Determinants of symptoms suggestive of gastroesophageal reflux disease in the elderly

The study material consisted of 487 subjects from a stratified random sample of the non-institutionalized population of Turku aged 65 years or more (n = 24,937). The study was based on a population study on health status and sleeping habits of the elderly. Information on health status and medications was obtained by means of interviews and from the national health insurance records of the subjects. A postal questionnaire inquired about symptoms suggestive of gastroesophageal reflux disease (GERD). In univariate analyses, perceived poor health, insomnia, disability, depression, previous peptic ulcer, cholelithiasis, and bronchial asthma were associated with daily symptoms suggestive of GERD. Moreover, the symptoms were associated with the use of beta-blocking agents, benzodiazepines, and neuroleptic agents. In multivariate analyses, previous peptic ulcer, perceived poor health, insomnia, and use of benzodiazepines were independently associated with symptoms suggestive of GERD. In conclusion, the determinants of symptoms suggestive of GERD in the elderly differ from those reported in young and middle-aged subjects.

Prevalence and characteristics of symptomatic gastroesophageal reflux disease in the elderly

OBJECTIVE

To study prevalence and characteristics of symptomatic gastroesophageal reflux disease in the elderly.

DESIGN

Survey by questionnaire of stratified random sample.

SETTING

City of Turku, Finland.

SUBJECTS

Population-based random sample consisting of non-institutionalized subjects aged 65 years or over. A questionnaire was sent to 559 subjects. The response rate was 92%. Twenty-nine incompletely filled forms were rejected. Thus, the questionnaires from 487 subjects, representing 87% of the original number, constitute the basis for the study.

MEASUREMENTS

The questionnaire inquired about the following symptoms: heartburn, regurgitation, chest pain, dysphagia, dyspepsia, respiratory symptoms, vomiting, and belching.

RESULTS

The age-adjusted prevalence of daily symptoms suggestive of gastroesophageal reflux disease was 8% in men and 15% in women (P < 0.05). Fifty-four percent of men and 66% of women reported that they had symptoms at least once a month (P < 0.05). The prevalence of symptoms was roughly the same across age groups. The occurrence of chest pain, dyspepsia, vomiting, belching, dysphagia, chronic cough, hoarseness, and wheezing were associated with symptoms suggestive of gastroesophageal reflux disease.

CONCLUSIONS

Symptoms suggestive of gastroesophageal reflux disease are common in elderly subjects. Women suffer from these symptoms more frequently than men. Typical reflux symptoms are often associated with atypical complaints, such as abdominal symptoms, chest pain, or respiratory symptoms.

Prevalence of oesophagitis in asthmatics

The exact relation between gastro-oesophageal reflux and asthma remains poorly understood. To determine whether gastro-oesophageal reflux in asthmatics results in oesophagitis, endoscopy and oesophageal biopsy were performed on 186 consecutive adult asthmatics. The presence or absence of reflux symptoms was not used as a selection criterion for asthmatics. Endoscopy was performed by two endoscopists using predefined criteria. All asthmatics had discrete wheezing and either a previous diagnosis of asthma or documented reversible airways obstruction of at least 20%. The oesophageal mucosa was graded as normal if no erosions or ulcerations were present in the tubular oesophagus; as oesophagitis if a mucosal break with exudate (erosions and/or ulcerations) was present; and as Barrett's if specialised (intestinal) columnar epithelium was present. A hiatal hernia was diagnosed if greater than or equal to 2 cm of gastric mucosa appeared above the diaphragm during endoscopy. Thirty nine per cent of the patients with asthma had oesophagitis or Barrett's oesophagus, or both. There was no difference in the oesophageal mucosal status between asthmatics who required and those who did not require bronchodilators. Fifty eight per cent of asthmatics had a hiatal hernia. It is concluded that oesophagitis is common and independent of the use of bronchodilator therapy in asthmatics.

Gastro-oesophageal reflux and severity of pulmonary disease in cystic fibrosis

The correlation between oesophageal dysfunction (OD), pathologic gastro-oesophageal reflux (GOR), and severity of pulmonary disease was studied in 12 patients with cystic fibrosis (CF). They were interviewed about symptoms of OD and underwent 24-h pH recording in the oesophagus, oesophageal manometry combined with reflux provocation tests, the acid perfusion test, the acid clearance test, lung function tests, and scoring of the chest radiograph. Six of the 12 patients reported symptoms of OD. Abnormal GOR, as shown by 24-h pH monitoring of the oesophagus, was found in eight of them. Altogether 9 of the 12 participants had at least one pathologic oesophagus test result. Results of radiologic examinations of the oesophagus, performed in six patients, were pathologic. The four patients with the best chest radiograph scores and the best lung function had significantly less signs and symptoms of OD and GOR than the other eight patients. We conclude that OD, GOR, and pulmonary disease covariate in CF.

Effect of salbutamol on gastroesophageal reflux in healthy volunteers and patients with asthma

The aim of this work was to establish whether beta-adrenergic agonists promote or increase gastroesophageal reflux in patients with asthma. Ten healthy individuals and eight patients with asthma were studied on 2 different days. One day they received a placebo, and the other day they received 4 mg of salbutamol by mouth. Complete measurements of esophageal manometry were performed before and every 30 minutes for 210 minutes after the administration of the drugs. Esophageal pH was measured continuously for the duration of the experiment. The results demonstrate that (1) salbutamol had no effect on the lower esophageal sphincter pressure gradient, the peak esophageal contraction pressure, or the number and duration of reflux episodes in patients with asthma and normal individuals, and (2) patients with asthma have a resting lower esophageal sphincter pressure higher than healthy subjects. We conclude that the administration of salbutamol does not affect esophageal function.

The actions of some beta-receptor agonists and xanthines on isolated muscle strips from the human oesophago-gastric junction

Isolated preparations from the circular muscle layer of the human oesophago-gastric junction were mounted in organ baths and isometric tension recorded. During an equilibration period, active resting tension developed suggesting that the preparations were representing the lower oesophageal sphincter. Active tension was abolished by exposing the preparations to Ca(++)-free medium. The two xanthines theophylline and enprofylline almost equipotently relaxed the preparations in a concentration-dependent manner (10(-7)-10(-3) M). Within therapeutic concentrations, theophylline inhibited active resting tension by 30-60%, while enprofylline lowered tension by less than 20%. Inhibitory actions of adenosine were demonstrated, and this suggests that adenosine antagonism is not the mechanism of action for xanthines in the oesophagus. Non-selective beta-receptor stimulation with isoprenaline inhibited active tension by 70% (10(-7) M), while beta 2-receptor stimulation with terbutaline inhibited tension by 47% (10(-5) M). Dobutamine, believed to preferentially stimulate beta 1-receptors, inhibited active tension in a concentration-dependent manner (10(-7)-10(-4) M). Metoprolol (10(-6) M), a selective beta 1-receptor antagonist, shifted the concentration-response curve for isoprenaline to the right, but left the maximal response unchanged. It is concluded that xanthines and beta-receptor agonists have inhibitory actions on circular muscle from the human oesophagogastric junction. The experimental data suggest the presence of beta 1- as well as beta 2-receptors, both mediating inhibition of active resting tension.

Most asthmatics have gastroesophageal reflux with or without bronchodilator therapy

The relationship between gastroesophageal reflux and asthma has not been clearly defined. We measured the lower esophageal sphincter pressures and studied gastroesophageal reflux patterns over 24 hours using an ambulatory Gastroreflux Recorder (Del Mar Avionics, Irvine, CA) in 44 controls and 104 consecutive adult asthmatics. The presence or absence of reflux symptoms was not used as a selection criterion for asthmatics. All asthmatics had discrete episodes of diffuse wheezing and documented reversible airway obstruction of at least 20%. Patients underwent reflux testing while receiving, if any, their usual asthmatic medications: 71.2% required chronic bronchodilators and 28.8% required no bronchodilators. Compared with controls, asthmatics had significantly decreased lower esophageal sphincter pressures, greater esophageal acid exposure times, more frequent reflux episodes, and longer clearance times in both the upright and supine positions (P less than 0.0001 for all parameters tested). There were no differences in any of the measured reflux parameters between asthmatics who required bronchodilators and those who did not. Thus, the decreased lower esophageal sphincter pressures and increased levels of acid reflux in asthmatics were not entirely caused by the effects of bronchodilator therapy. Receiver-operating characteristic analysis generated reflux values that discriminated asthmatics from controls. More than 80% of adult asthmatics have abnormal gastroesophageal reflux. We conclude that most adult asthmatics, regardless of the use of bronchodilator therapy, have abnormal gastroesophageal reflux manifested by increased reflux frequency, delayed acid clearance during the day and night, and diminished lower esophageal sphincter pressures.

Effect of positions, eating, and bronchodilators on gastroesophageal reflux in asthmatics

Gastroesophageal reflux is common in asthmatics. To determine whether bronchodilators, the supine position, or eating affect gastroesophageal reflux, we performed ambulatory 24-hr pH monitoring on 44 controls and 104 unselected adult asthmatics. All asthmatics had discrete attacks of wheezing and documented reversible airway obstruction of at least 20%. The presence or absence of gastroesophageal reflux symptoms was not used as a criterion for patient selection. Chronic bronchodilator therapy was required by 71.2% of the asthmatics, and was continued during the test. Asthmatics had significantly worse GER than controls during the 3-hr postprandial period, which continued into the nonpostprandial period up to the next meal. Significant differences were present for esophageal mucosal acid contact time, frequency of reflux episodes, and clearance times. During the nonpostprandial periods asthmatics had four times the acid reflux as controls and 19-fold the frequency of prolonged reflux episodes. There were no differences between asthmatics on bronchodilators and those not on bronchodilators in any of the reflux parameters during the upright (postprandial, nonpostprandial) period or supine (sleep) period (P = NS). We conclude that: (1) regardless of the use of bronchodilator therapy, asthmatics have significant GER when asleep and after meals that continues beyond the postprandial period to the next meal; and (2) asthmatics receiving bronchodilators have similar gastroesophageal reflux patterns after eating, in the nonpostprandial period, and when asleep as asthmatics not receiving bronchodilators.

Physostigmine and metoclopramide in oesophageal peristaltic spread in man

Simultaneous recordings of electrical and mechanical activities at different levels of the oesophagus were performed in normal men before and after physostigmine and metoclopramide injections. Various parameters of the basal oesophageal peristalsis were significantly modified following drug treatment. In particular, physostigmine injections induced a shortening of electromechanical coupling time and a reduction of the propagation velocities of the electrical and mechanical oesophageal events. Metoclopramide shortened the electromechanical coupling time but increased the electrical and mechanical propagation velocities along the oesophagus.

Beta-adrenoceptor blockade does not modify gastrointestinal transit time in healthy volunteers

The effect of non-selective beta-adrenoceptor blockade on gastrointestinal transit time (GITT) was measured in 20 healthy volunteers with a radiographic method. By means of double-blind, crossover technique, each subject was studied during treatment with 80 mg oral propranolol or placebo twice daily for 7 days. The number of radiopaque markers retained in the alimentary tract did not differ significantly between the placebo and the propranolol periods. The mean GITT for placebo was 78 h and for propranolol 77 h. During propranolol treatment the heart rate and blood pressure were significantly decreased. It is concluded that non-selective beta-adrenoceptor blockade does not influence human gastrointestinal transit time under unstrained conditions.

Effects of thoracic epidural analgesia with morphine or bupivacaine on lower oesophageal motility--an experimental study in man

Lower oesophageal peristalsis and lower oesophageal sphincter (LOS) pressure during thoracic epidural analgesia (TEA) were studied in 20 healthy volunteers. After oesophageal manometric baseline recordings, 10 volunteers received 4 mg epidural morphine. The other ten received 0.5% bupivacaine epidurally in sufficient amounts to block the sympathetic innervation of the oesophagus. Thereafter oesophageal manometry was repeated. During epidural morphine oesophageal peristalsis, resting LOS pressure and the contraction of LOS after swallowing did not change, but the relaxation of the LOS in response to swallowing decreased significantly (P less than 0.01). Following TEA with bupivacaine, neither distal oesophageal peristalsis nor LOS pressure changed.

Effects of upper dorsal sympathectomy on esophageal motility in humans

To evaluate the role of the sympathetic nervous system in modulating esophageal motility, esophageal manometry was performed on two groups of patients who underwent upper dorsal sympathectomy for relief of palmar hyperhydrosis. In six patients sympathectomy was done by the supraclavicular approach, with removal of T2 and T3 ganglia. Manometry was performed before the operation and three weeks after it. In seven other patients sympathectomy was done by the axillary approach, with removal of T2-T4 ganglia. Manometry in this group was performed 28.4 +/- 22.4 months after the operation. Fifteen individuals with an intact sympathetic system served as controls. Manometric parameters evaluated were esophageal contraction amplitude and duration and lower esophageal sphincter pressure. The difference between the results obtained in the pre- and postoperative periods in the first group was not statistically significant. The differences between the two patient groups and between the patient groups and the control group were not statistically significant either. We conclude that upper dorsal sympathectomy does not affect esophageal motility in man.

Esophageal spasm following propranolol overdose relieved by glucagon

A case of propranolol overdose complicated by esophageal spasm preventing extrication of an orogastric lavage tube and relieved by intravenous glucagon is presented. Esophageal spasm is an infrequent complication of beta-adrenergic over-dose. Possible mechanisms of esophageal spasm and its relief with glucagon are discussed.

Beta adrenergic influence on oesophageal peristalsis in man

The effects of the beta-1 adrenergic agonist prenalterol and the beta-2 adrenergic agonist terbutaline on oesophageal peristalsis were studied in nine healthy volunteers with pressures recorded in the proximal, middle, and distal oesophagus. Two doses of the agonists were given after pretreatment with placebo, propranolol, or metoprolol in a double blind randomised fashion. Terbutaline 0.25 +/- 0.25 mg iv decreased peristaltic pressure in middle oesophagus from 8.1 +/- 1.1 to 5.1 +/- 0.8 kPa (p less than 0.01) and in the distal oesophagus from 9.5 +/- 1.0 to 4.7 +/- 0.6 kPa (p less than 0.001). Peristaltic velocity was decreased in the distal oesophagus after terbutaline from 3.3 +/- 0.2 cm/sec to 2.9 +/- 0.2 cm/sec (p less than 0.05). Prenalterol 1 mg iv was followed by a decrease of peristaltic pressure in the middle oesophagus from 10.2 +/- 1.3 to 7.7 +/- 1.1 kPa (p less than 0.01) and a decrease of peristaltic velocity in upper oesophagus from 3.6 +/- 0.2 to 3.3 +/- 0.1 cm/sec (p less than 0.05) while no significant changes were seen in the distal oesophagus. Pretreatment with the beta-1 blocker metoprolol 15 mg iv blocked the effects of prenalterol 1 mg iv but not the effects of terbutaline. Propranolol 10 mg iv blocked the effects of terbutaline on peristaltic pressure. After metoprolol infusion mean distal peristaltic amplitude was 11.9 +/- 0.8 kPa compared with 8.5 +/- 1.2 kPa after placebo (p less than 0.01). It is concluded that both beta-1 and beta-2 adrenoceptor stimulation significantly decrease oesophageal peristaltic pressure in man. The body of the oesophagus seems to be under beta adrenergic inhibitory influence under physiological conditions.

Rectosigmoid motility response to beta-adrenoceptor stimulation in patients with the irritable bowel syndrome

Patients with the irritable bowel syndrome were studied with regard to the effects of beta-adrenoceptor agonists on rectosigmoid motility. Pressure was recorded with a continuously inflated balloon in the upper rectum and recorded from a pressure catheter in the sigmoid colon. On different days the beta-2 agonist terbutaline, the beta-1 agonist prenalterol, and placebo, respectively, were administered intravenously after a control period. During each examination contractile activity was quantified for three consecutive periods of 25 min. Terbutaline in a total dose of 0.50 mg decreased sigmoid motility index significantly from 3.0 +/- 0.6 (SEM) to 1.1 +/- 0.3 kPa X min (p less than 0.01). After less than or equal to 5 mg prenalterol no significant changes of motility index were observed. After placebo an increase, although not significant, in contractile activity was seen compared with the initial control period. Rectal motility indices were low and not changed by the beta agonists. The serum concentrations of the drugs were within the therapeutic limits used in clinical practice and caused a dose-dependent increase of both systolic blood pressure and heart rate. It is concluded that beta-2 adrenoceptor stimulation significantly decreases sigmoid motility whereas the motility index seems to be unaffected by beta-1 adrenergic stimulation.

Effects of beta-adrenoceptor stimulation on rectosigmoid motility in man

Effects of selective beta-adrenoceptor agonists on rectosigmoid motility during prolonged rectal distension were studied in 12 healthy volunteers in a double-blind, randomized fashion. Continuous distension was performed with a balloon in the proximal part of the rectum. Pressure was recorded by this balloon and by a catheter in the sigmoid. Contractile activity was quantified for three consecutive periods of 25 min. On separate days prenalterol (beta-1 agonist), terbutaline (beta-2 agonist), and placebo, respectively, were administered intravenously preceded by a control period. Terbutaline, 0.5 mg intravenously, was followed by a significant decrease of sigmoid motility from 4.3 +/- 1.5 (SEM) kPa X min to 2.9 +/- 1.0 kPa X min (P less than 0.01) and of rectal motility from 4.3 +/- 1.3 to 2.4 +/- 0.7 kPa X min (P less than 0.05). After placebo a slight, but not significant, increase of contractile activity was seen compared to the initial control period. The effects of prenalterol, 1.0 and 4.0 mg intravenously, on motility did not differ from that of placebo infusion. Both drugs caused a dose-dependent increase of systolic blood pressure and of heart rate. The study shows that beta-2-adrenoceptor stimulation decreases rectosigmoid colonic pressure in man, while effects of beta-1 stimulation on motility index do not differ from that of placebo.

Beta adrenergic influence on esophageal and colonic motility in man

Gastrointestinal (GI) motility is centrally controlled through the sympathetic and parasympathetic nerves, sympathetic effects being partly mediated by beta adrenoceptors. Although beta adrenoceptor agonists and antagonists are widely used for different disorders, little is known about the influence of these agents on GI motility. The present study was initiated to investigate whether there is a physiological, beta adrenergic influence on human GI motility and to describe the effects of selective beta adrenoceptor stimulation on motility in the proximal and distal parts of the GI tract. Esophageal peristalsis was measured in healthy subjects using electronic catheters. Distal colonic motility was measured with an open-tipped, water-perfused catheter in the sigmoid colon and from an air-filled balloon in the rectum in healthy subjects and in patients with the irritable bowel syndrome (IBS). In one study, colonic motility was stimulated with continuous infusion of the octapeptide of cholecystokinin (CCK-OP). Esophagus: Peristaltic amplitude was increased in the distal smooth muscle part of the esophageal body after infusion of both the nonselective beta blocker propranolol and the beta-1 selective blocker metoprolol. After infusion of the beta-1 agonist prenalterol and the beta-2 selective agonist terbutaline, a profound decrease in esophageal peristaltic amplitude was seen. Pretreatment with metoprolol selectively blocked the response to a moderate dose of prenalterol but did not block the response to terbutaline. The latter response was blocked by propranolol. Peristaltic velocity in the proximal part of the esophagus was decreased by beta-1 stimulation and in the distal part by beta-2 stimulation. Distal colon: In healthy subjects the sigmoid motility index showed a dose-dependent increase after metoprolol and propranolol, respectively. The increase was more marked after propranolol infusion. Terbutaline decreased the sigmoid motility index both in healthy subjects and in patients with the IBS. Furthermore, the rectal motility index was decreased in the group of healthy subjects. The effects of prenalterol on rectal and sigmoid motility did not differ from those of placebo. The IBS patient group showed larger intraindividual variations in sigmoid motility from day to day and also lower rectal motility indices than the healthy subjects. Infusion of CCK-OP increased the sigmoid motility index compared to non-stimulated conditions. No effects on CCK-OP stimulated motility were seen after either terbutaline, prenalterol or placebo.(ABSTRACT TRUNCATED AT 400 WORDS)

Effects of beta-adrenoceptor blocking drugs on human sigmoid colonic motility

Effects of propranolol and metoprolol on sigmoid colonic motility were studied in 12 healthy volunteers in a double-blind randomized fashion. Colonic pressure was recorded 15-18 cm from anus and contractile activity quantified for periods of 25 min. On separate days propranolol, metoprolol, and placebo, respectively, was administered intravenously preceded by a control period. After propranolol, 10 mg intravenously, pressure activity increased significantly from 3.8 +/- 1.1 (SEM) kPa X min (28 +/- 8 mm Hg X min) to 5.9 +/- 1.0 kPa X min (44 +/- 8 mm Hg X min) (P less than 0.001). Also, after propranolol, 5 mg intravenously, the pressure activity was increased (P less than 0.05). After metoprolol, 10 mg intravenously, contractile activity increased from 4.3 +/- 0.9 kPa X min (32 +/- 7 mm Hg X min) to 6.1 +/- 1.0 kPa X min (46 +/- 8 mm Hg X min) (P less than 0.01). The two drugs caused equipotent reduction of heart rate. After placebo, no effect on sigmoid pressure or heart rate was observed. The study shows that unselective (propranolol) and beta 1-selective (metoprolol) beta-blocking drugs enhance distal colonic pressure in man. Colonic motility seems to be under sympathetic beta-adrenergic influence even under fairly unstrained conditions.

Effect of propranolol on the lower oesophageal sphincter in man

The effect of an intravenous dose (2 mg) of propranolol in the lower oesophageal sphincter was studied in 10 human volunteers. A hydraulic-capillary infusion manometric technique was used to measure the lower oesophageal sphincter pressure. A significant increase in sphincter pressure was recorded, together with increased amplitude and duration of oesophageal peristaltic activity. This study confirms the presence of specific beta-receptors in the lower oesophageal sphincter.

Somatostatin effects on lower esophageal sphincter function

The effect of somatostatin (GH-RIH) infusion (2 microgram/min) on lower esophageal sphincter pressure (LESP) responses to various stimuli was evaluated in adult male baboons. GH-RIH infusion did not affect basal LESP, but did cause a significant suppression of mean immunoreactive insulin (IRI) to 5.8% of basal values (P less than 0.05). Pentagastrin IV caused dose-related increases in LESP that were unaffected by GH-RIH. Abdominal compression caused a threefold rise in LESP (P less than 0.005) both without and with GH-RIH. However, atropine (20 microgram/kg iv bolus) completely blocked this cholinergic LES pressure response. Intragastric alkali as well as intragastric glycine caused significant increases in LESP (P less than 0.05). These LESP responses to alkali and to glycine were totally abolished by GH-RIH. In conclusion, GH-RIH infusion in the baboon does not affect basal LESP, LES smooth muscle response to exogenous stimulation, nor a cholinergically mediated LES response. GH-RIH does inhibit the response of LESP both to intragastric alkali and to glycine by the apparent suppression of a hormonally mediated mechanism.

Clinical pharmacology and therapeutics of the oesophagus and the lower oesophageal sphincter

Oesophageal function can be studied with intraluminal manometry, indwelling pH electrodes or with in vitro methods using isolated tissue. Radiology and endoscopy are the main diagnostic procedures. Innervation of the body of the oesophagus is mainly cholinergic, but the lower oesophageal sphincter appears to be affected by a wide range of biogenic substances, such as autonomic transmitters, polypeptide hormones and prostaglandins. Most drugs used in the treatment of oesophageal disorders act by modifying the action of the naturally occurring agents.

Symposium on gastrooesophageal reflux and its complications. 6. Surgical treatment

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Lower esophageal sphincter relaxation: studies on the neurogenic inhibitory mechanism

The purpose of this study was to determine the physiological mechanism of lower esophageal sphincter (LES) relaxation. Circular muscle of the esophagus, LES, and stomach were evaluated for their inhibitory response to electrical stimulation during a maintained tonic contraction produced by a superfusion of acetylcholine and physostigmine. Only the circular muscle of the distal esophagus showed an inhibitory response to electrical stimulation. The maximal inhibition of LES muscle was 63.9+/-5.9 (mean+/-SE)% of the acetylcholine produced tension and occurred at 80 V. Upper esophageal and gastric muscle were not inhibited. The inhibitory response of the LES muscle was antagonized by tetrodotoxin and hexamethonium but not by other specific antagonists. Adrenergic nerve destruction following 6-hydroxydopamine also did not abolish the LES inhibition. These data indicate that the distal esophagus, at the zone of the manometrically determined LES, is characterized by a nonadrenergic neural inhibitory system. We suggest that these nerves may mediate LES relaxation.