Esophageal aperistalsis and achalasia produced in dogs by prolonged cholinesterase inhibition.

Considerable evidence suggests that cardiospasm, or achalasia of the esophagus, is a disease of the intrinsic innervation of that organ (1-6). If so, a neurotoxic agent might produce a similar picture in experimental animals. This possibility is enhanced by the report of Koelle and Gilman (7) who, while studying the effects of prolonged administration to dogs of the anticholinesterase agent di-isopropylfluorophosphate (DFP), noted the appearance of objective evidences of dysphagia, esophageal stasis, and "cardiospasm." However, not all motor dysfunctions causing dysphagia and esophageal stasis in man are manifestations of cardiospasm, and no studies have been performed to show that DFP-induced canine "cardiospasm" is indeed analogous to the condition seen in man. Consequently, we undertook to see if 1) prolonged DFP administration does regularly produce an esophageal motor disorder in dogs, and 2), if so, to determine its nature and its similarity to human cardiospasm.