Pacesetter potential of the human gastroduodenal junction

Abstract

SheffieldSUMMARY The pacesetter potential of the gastric antrum and proximal duodenum has been recorded in man by electrodes placed under the serosal coat of the gut. The typical 3 cycle/min of the stomach was found to be conducted across the pylorus into the first part of the duodenum at a rate (2 cm/sec) about four times as fast as its conduction in the more proximal antrum (0.5 cm/sec). A 3 cycle/min pacesetter potential could be detected as far distally in the duodenum as 10 cm from the pylorus.Rhythmic electrical waves are present in the smooth muscle of the stomach and the duodenum at all times, even when motor activity is in abeyance. These electrical cycles are known as the pacesetter potentials. When motor activity occurs, another type of electrical activity, known as spike activity or action potentials, is present during the latter part of the pacesetter potential. 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, and Bogoch, 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. MethodStainless steel electrodes, 0-25 mm in diameter, were implanted just under the serosa of the distal 4 cm of the gastric antrum and the proximal 12 cm of the duodenum in 10 subjects, aged 28 to 52 years, undergoing cholecystectomy. The procedure was fully explained and informed consent was given by the patients. Two gastric electrodes were placed

The immediate and delayed effects of different types of vagotomy on human gastric myoelectrical activity.

“…The mean frequency of this electrical activity was 3 07 ± 0 04 c/m and in no patient did it vary more than ± 0-15 c/m. These results are similar to previous measurements of antral myoelectrical activity in preoperative patients recorded in this department (Duthie, Kwong, Brown, and Whittaker, 1971;Stoddard et al, 1973b). After vagotomy Two patients, one following HSV and one following TV + P, had irregular activity present for the entire control recording period and their studies are considered separately in greater detail below.…”

A pilot study of botulinum toxin injection for the treatment of delayed gastric emptying following esophagectomy

“…However, interdigestive pyloric motor activity has been demonstrated at 12 months after esophagectomy [15]. An increase in amplitude of motor contractions and reappearance of the migrating motor complex has also been demonstrated after vagotomy [5,7]. These findings explain the observation that symptoms of postprandial fullness and nausea that are so common after esophagectomy will often improve with time.…”

Postprandial Electrogastrographic Changes with or without Parasympathetic Nerve Blockade.

“…It is usually found in normal subjects (Nelsen et al, 1968;Duthie et al,1971 ;Kaneko et al,1995). Its onset is probably mediated by the physical distention of the stomach due to food ingestion.…”

“…Visual inspection was performed to determine the presence or absence of the transient frequency decrease (0.02 to 0.03 Hz), postprandial dip, which is usually found in the EGG in normal subjects (Nelsen et al, 1968 ;Duthie et al, 1971 ;Kaneko et al,1995) immediately after food intake ( Figure 3). 0.8 mg/kg of scopolamine (TANABE SEIYAKU CO., LTD, Osaka, Japan), an anticholiner gic agent, was intravenously administered in the right forearm of the subject after 20 minutes recording of normal EGG, and followed by 20 minutes recording.…”