A Study of the Cardia in Unanesthetized Dogs. ∗

Abstract

Gastric and œsophageal fistulaæ have been made in 15 dogs for the purpose of studying the activity of the cardia and stomach following stimulation of the œsophagus. For recording changes in tonus a small balloon about 3 cm. long containing rubber sponge with a diameter of 0.5 to 1 cm. was used in the cardia and a large balloon in the stomach. The balloon in the cardia was attached to a fairly rigid tube such that it could be held in place by the hand. It was attached to a tambour and the stomach balloon to a chloroform manometer for recording. A third balloon was placed in the œsophageal fistula well above the cardia. When a stimulus was desired the operator blew into the tube to this balloon distending it. It thus acted as a lodged bolus that could be called into play and allowed to disappear at will. Dogs were trained to lie quietly while tracings were being taken and no anesthesia was used.

Fig. 1 shows the response following distension of the upper balloon in the œsophagus in an animal without nerve section. A relaxation of the cardia and cardiac portion of the stomach (receptive relaxation) takes place immediately. Cutting one vagus did not alter this inhibitory response in the cardia and stomach. In 3 dogs section of both vagi above the diaphragm failed to produce any recognizable spasm of the cardia nor did it cause a material alteration in the inhibition seen in the cardia and stomach following distension of the œsophagus. The response was not affected in 3 dogs with splanchnics cut. Two dogs have had both vagi cut (above the diaphragm) and splanchnics cut.