A relation between gastroduodenal muscle contractions and gastric emptying

Studies of gastric emptying in dogs, rats, and man have demonstrated that solutions of various substances empty in a characteristic manner. This topic has been reviewed by Hunt (1963). The rate of emptying of test meals from the stomach is influenced by many factors, including volume (Hunt and Macdonald, 1954), osmotic pressure (Hunt, 1956), titratable acidity (Hunt and Knox, 1962), and chemical composition (Elias, Gibson, Greenwood, Hunt, and Tripp, 1968; Hunt and Knox, 1968). Thomas (1957) has reviewed motor patterns of the gastroduodenal area which have been characterized when various substances are placed in the stomach. These studies were usually done with balloons or open-tip catheters. Such devices are obstructive to the normal flow of gastric contents and may initiate reflexes that can alter gastric emptying time. Radiological methods have also been used but the data obtained by these methods are subjective and difficult to quantify. Louckes, Quigley, and Kersey (1960) utilized the inductograph, an extraluminal recording device, to study the contractile pattern of the 'pyloric region' but did not quantify their results. Another type of extraluminal device has been developed (Jacoby, Bass, and Bennett, 1963). This unit avoids mucosal contact and the data obtained may be quantified. In this study extraluminal force transducers were used to monitor gastric and duodenal smooth muscle contractions in intact unaesthetized dogs. The gastric emptying rate of trisodium citrate and glucose and that of the fat substance test meals and their influence on smooth muscle contractions were evaluated.