Transmission of electrical activity through the gastroduodenal junction

Abstract

The electrical and mechanical activities of the gastroduodenal junction were studied in isolated cat preparations, using the pressure-electrode technique. The spontaneous electrical activity of the pyloric antrum consists of periodic depolarizations, the configuration of which is somewhat more complex than that of comparable potentials recorded from the longitudinal muscle layer of the small intestine. Like their intestinal counterparts these antral slow waves may be associated with spike potentials which are thought to initiate contractions. The electrical activity at the gastroduodenal junction consists of a combination of antral and duodenal slow waves, sometimes accompanied by spike potentials. In the proximal duodenum, antral slow waves are represented by periodic depolarizations which may be associated with spike potentials followed by contractions. Because of the extension of the antral slow waves into the proximal duodenum, contractions initiated in the antrum may also extend into the proximal duodenum. It is concluded that the gastroduodenal junction is a transition zone, coordinating the electrical and corresponding mechanical activities of the antrum and proximal duodenum.

Organization of electrical activity in the canine pyloric canal.

“…Bass et al (1961) found that gastric slow waves did not traverse the pylorus, and pyloric and duodenal activities were dissociated. Others (Bortoff & Weg, 1965;Bortoff & Davis, 1968) have reported that gastric slow waves can spread to the duodenum in the cat.…”

Pacesetter potential of the human gastroduodenal junction

“…It was generally held that the pacesetter from the antrum of the stomach does not pass beyond the pylorus in animals (Allen, Poole, and Code, 1964) and the pylorus was termed an 'electrical insulator' (Bass, Code, and Lambert, 1961). However, in animal experiments, some workers have detected antral activity in the pylorus itself (Llanfranchi, Barbara, and Bartolotti, 1968) and in the duodenum (Daniel, Carlow, Wachter, Sutherland, andBogoch, 1959: Bortoff andWeg, 1965;Bortoff and Davis, 1968). We have studied this question in man, using implanted electrodes, and have found that the pacesetter potential is conducted from the stomach to the duodenum.…”

Motor Activity of the Duodenum in Man: Correlation with Antral Contraction

“…As to the distension of the intestinal wall, the basal gastric secretion seems normally too low to have any mechanical effect on the duodenum. However, the role of gastric electrical waves in setting off contractions must be reexamined since Bortoff et al have shown in different animal species that these waves were feebly propagated beyond the pylorus [5] and that their depolarizing effect, adding itself to that of the slow electrical duodenal waves, resulted in an increase in the number of action potentials [4], It must be noted that this myogenic transmission of the gastric pace-setter potentials was not demonstrated 2 cm beyond the pylorus. Our case observations in man in conditions similar to those used by Bortoff in the animal confirm that approximately 1 cm below the pylorus the gastric pace-setter potentials are still visible, but very greatly diminished [7].…”