The Progress Of Research Of The Effects Of Calcium Channel On Regulatory Mechanism Of Contraction And Relaxation Of The Human Lower Esophageal Sphincter

The existence and structural equivalent of the lower esophageal sphincter(LES)in human beings have been a matter of speculation for many years.After studying the anatomy of 32 cadavers,Liebermann-Meffert et al described the arrangement of the smooth muscles at the esophagogastric junction(EGJ)in detail.They demonstrated that the musculature of the human LES consisted of sling fibers and clasp fibers.LES clasp fibers is a semi-circular in the right side,while sling fibers is U-shaped band hoisted in the gastroesophageal junction.Both muscle muscles maintain the closure status of the LES,and form a high-pressure zone(HPZ,15～30mmHg).This theory laid the foundation for further studies on the physiology,pathology and pharmacology of the LES.From then on,some reseachers have inveinvestigated the physiology and regulation mechanism of LES from different animals,and found that LES had differnt property different from other smooth muscle structure.And more importantly,there are also great differences in the sling fibers and clasp fibers.Therefore,the abnormal of LES structure and function may be the pathological basis of a variety of esophageal diseases.It has been demonstrated that the liberation of intracellular Ca²⁺is important in the smooth muscle contraction process,just like "the second messenger".The contaction of smooth muscle cells depends on intracellular concentration of Ca²⁺.High concentration of Ca²⁺causes the smooth muscle contraction, low concentration of Ca²⁺causes sdiastole.Ca²⁺generating smooth muscle contraction is from extracellular fluid Ca²⁺ influx and the release of the intracellular Ca²⁺(mainly from sarcoplasmic reticulum,SR).The extracellular fluid Ca²⁺influx through the protoplasmic membrane calcium ion channel,and the release of the Ca²⁺from intracellular stores also passes the calcium ion channel.The calcium ion channel exists in all the excitatory cells as well as some non-excitatory cells and even the nucleus biology.Similar to the skeletal muscle and the cardiac muscle,the calcium ion channel is playing the pivotal role in contraction and diastole of the smooth muscle cells.And L-calcium channel in the mebrane of the smooth muscle cells has been shown to affect excited-contraction pair.When depolarization of smooth muscle cell membrane,Ca²⁺flows through the L-calcium channel is a triggering factor generating smooth muscle cell contraction.This research using Smooth muscles of the sling and clasp fibers were obtained from who underwent subtotal esophagectomy for middle thoracic esophageal carcinoma.The application of in vitro muscle tension were determined in the technology of a solution of calcium or calcium in the sling fibers and clasp fibers of acetylcholine different reaction.And observation of different types of calcium channel blockers and signal transduction channel blockers different responses to acetylcholine,which is to determine differences of the link above,the two fibers to clarify the different roles in the LES.Then we will have further understanding about gastroesophageal reflux disease and esophageal motor dysfunction in the pathophysiology of the disease mechanism. accordingly we will have penetrate deeply approach mechanism for esophageal motor function disorders and gastroesophageal reflux disease treatment and put forward a new theory,to explore new ideas,new methods.