Revista española de enfermedades digestivas : organo oficial de la Sociedad Española de Patología Digestiva vol:91 issue:10 pages:711-5
The esophageal primary motor disorders like achalasia, diffuse esophageal spasm or the nutcracker can involve the upper esophageal sphincter, the esophageal body, the lower esophageal sphincter or a combination of them. This article will focus on the esophageal body and abnormal peristalsis. A normal esophageal peristaltic contraction occurs after a latency period following a swallow and requires a minimum amplitude to be propulsive. Abnormal latencies may generate simultaneous contractions whereas low amplitude contractions may be inefficient i.e. GERD and high amplitude contractions my provoke chest pain or dysfagia i.e. diffuse spasm. The latency period between deglutition and contraction is due to a muscle inhibition immediately after the swallow. This inhibition is due to release of NO by an inhibitory neurone located in the myenteric plexus. At the end of the inhibition, the contraction occurs due to release of acetyl choline by an excitatory cholinergic neurone. The exact interplay between these two neurones will determine the <<timing>> or propagation velocity and the amplitude of esophageal contractions. Patients with achalasia have a predominant loss of inhibitory neurones (VIP and NOS) with a relative preservation of excitatory cholinergic neurones. The histophatologic and immunohistochemical status in patients with esophageal primary motor disorders other than achalasia is poorly characterised Examples of deglutitive inhibition in the esophagus can be observed during the relaxation of the lower esophageal sphincter or when a subject swallows very frequently. In order to quantify deglutitive inhibition we developed a method that induces an artificial high pressure zone in the mid esophageal body. During the latency period after a swallow, the high pressure zone relaxes (is inhibited). With this method, we could measure the magnitude and duration of the inhibitory phenomenon. There is a very good correlation between the degree of deglutitive inhibition and propagation velocity of esophageal contractions. The less inhibition, the faster the propagation velocity of contractions. Simultaneous contractions are the consequence of absent inhibition. Patients with esophageal primary motor disorders may have very fast propagating contractions and a small percentage of simultaneous contractions or up to 100% of simultaneous contractions. The correlation between the degree of inhibition and propagation velocity of contractions suggests that the different primary motor disorders are the expression of a progressive failure in esophageal inhibition.