Responses of human clasp and sling fibers to neuromimetics

Abstract

The sensitivities and maximum responses to each agent differed between the clasp fibers and sling fibers. This suggests that the two kinds of fiber have different roles in establishing tension in the lower esophageal sphincter, with implications for the medical and surgical treatment of disorders in this region.

Quantitation of the Contractile Response Mediated by Two Receptors: M2and M3Muscarinic Receptor-Mediated Contractions of Human Gastroesophageal Smooth Muscle

“…This result is in general agreement with a previous study showing that human sling fibers contract significantly greater to acetylcholine than human clasp fibers (Tian et al, 2004). As shown here for the first time, sling fibers may contract greater than the other fibers because they have a greater total density of muscarinic receptors than all other muscles studied.…”

“…This theory laid the foundation for further studies on the physiology, pathology, and pharmacology of the GEJ. Over the span of the next three decades, the formation and regulation of the HPZ were closely studied with the help of high-resolution endoscopic ultrasound, esophageal manometry, autopsies, and animal experiments (Burleigh, 1979;McCray et al, 2000 human clasp and sling stomach muscle fibers in the sensitivity and maximal responses to acetylcholine, dopamine, phenylephrine, and isoproterenol (Tian et al, 2004). Differences in response to electric field stimulation (EFS) have also been reported between both the clasp and sling fibers shown to relax to EFS, whereas the areas caudal to this (stomach) contracted under EFS (Burleigh, 1979).…”

Pharmacologic Specificity of Nicotinic Receptor-Mediated Relaxation of Muscarinic Receptor Precontracted Human Gastric Clasp and Sling Muscle Fibers within the Gastroesophageal Junction

“…This result is in general agreement with previous studies showing that human gastric sling muscle fibers contract significantly greater to acetylcholine than human clasp muscle fibers (Tian et al, 2004). Over the span of the last 3 decades, the formation and regulation of the HPZ by the gastric sling and clasp muscle fibers have been studied in vitro.…”

“…Over the span of the last 3 decades, the formation and regulation of the HPZ by the gastric sling and clasp muscle fibers have been studied in vitro. Differences have been reported between human clasp and sling stomach muscle fibers in the sensitivity and maximal responses to acetylcholine, dopamine, phenylephrine, and isoproterenol (Tian et al, 2004).…”

“…However, the first barrier to gastric reflux is actually the clasp and sling muscle fiber complex of the proximal stomach. Several investigators also use this same term "lower esophageal sphincter" (LES) to indicate this clasp and sling muscle fiber complex (Gonzalez et al, 2004;Tian et al, 2004). The intrinsic inner circular muscles of the distal 2 to 3 cm of the esophagus (the lower esophageal circular muscles, LEC) together with the gastric sling/clasp fiber muscle complex constitute the internal, smooth muscle mechanism of the high-pressure zone.…”