title: Effect of drugs and electrical field stimulation on circular muscle strips from human lower oesophagus.
abstract: Sphincteric muscle from human lower oesophagus may be identifiable in vitro by its ability to develop a very high level of tone (sustained resting tension). Circular muscle strips from human lower oesophagus generally behave in a similar manner to strips from the opossum oesophagus with respect to development of tone, responses to electrical field stimulation and responses to a variety of drugs. Pharmacological analysis of responses to field stimulation in strips from the region of the oesophago-gastric junction suggests that the typical biphasic response (relaxation followed by an after-contraction) is mediated by nerves which are neither adrenergic nor cholinergic. Of the substances examined only vasoactive intestinal peptide (VIP) cannot be excluded as a possible candidate for the role of inhibitory transmitter. The mechanism producing the after-contraction is not clear but it would seem unlikely that this is simply a rebound contraction. The after-contraction can be blocked independently of the relaxation by a variety of agents and is potentiated by metoclopramide.
mesh_terms: D002217:Carbachol / Q000494:pharmacology; D015237:Dinoprost; D004558:Electric Stimulation; D004943:Esophagogastric Junction / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000187:drug effects; D009126:Muscle Relaxation / Q000187:drug effects; D009294:Narcotics / Q000494:pharmacology; D011460:Prostaglandins F / Q000494:pharmacology; D012701:Serotonin / Q000494:pharmacology; D013779:Tetrodotoxin / Q000494:pharmacology; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology
chemical_list: D009294:Narcotics; D011460:Prostaglandins F; D012701:Serotonin; D014660:Vasoactive Intestinal Peptide; D013779:Tetrodotoxin; D002217:Carbachol; D015237:Dinoprost