Electrical Activity of the Stomach: Clinical Implications CHUNG H. KIM, M.D.  Mayo Clinic Proceedings  Volume 61, Issue 3, Pages 205-210 (March 1986) DOI: 10.1016/S0025-6196(12)61851-5 Copyright © 1986 Mayo Foundation for Medical Education and Research Terms and Conditions

Fig. 1 Diagram showing location of gastric pacemaker in midcorpus along greater curvature of stomach. Spontaneous and rhythmic electrical potentials generated from pacemaker site are spread circumferentially and longitudinally toward pylorus. Mayo Clinic Proceedings 1986 61, 205-210DOI: (10.1016/S0025-6196(12)61851-5) Copyright © 1986 Mayo Foundation for Medical Education and Research Terms and Conditions

Fig. 2 Schematic representation of gastric electrical potentials. In intracellular recording, each slow wave is composed of an initial upstroke potential (1) followed by a plateau potential (2) and a subsequent return to baseline. Their extracellular counterparts are the initial potential (3) and the isopotential segment (4). The shape of action potentials differs from that of slow waves in that the amplitude of the plateau potential is greater in the intracellular recording and that the isopotential segment is replaced by a downward deflection known as the second potential (5) in the extracellular recording. Note that peaks of contractions coincide with peaks of plateau potentials and second potentials. Mayo Clinic Proceedings 1986 61, 205-210DOI: (10.1016/S0025-6196(12)61851-5) Copyright © 1986 Mayo Foundation for Medical Education and Research Terms and Conditions

Fig. 3 Normal electrical activity of the canine stomach (extracellular recording). Note well-defined and phasic slow waves, which propagate from the midcorpus all the way to the distal antrum in an antegrade fashion. The rate of the slow waves is 5 cycles per minute in the dog. Mayo Clinic Proceedings 1986 61, 205-210DOI: (10.1016/S0025-6196(12)61851-5) Copyright © 1986 Mayo Foundation for Medical Education and Research Terms and Conditions

Fig. 4 An example of canine tachygastria (extracellular recording). Note onset of abnormally fast slow waves in distal antrum, which later spread to the more proximal region of the stomach. Tachygastria is followed by a brief pause before normal electrical activity is resumed. Mayo Clinic Proceedings 1986 61, 205-210DOI: (10.1016/S0025-6196(12)61851-5) Copyright © 1986 Mayo Foundation for Medical Education and Research Terms and Conditions

Fig. 5 An example of drug-induced canine bradygastria (extracellular recording). Note that shortly after a bolus injection of met-enkephalin (arrow) slow waves appear abnormally slow in both the corpus and the antrum simultaneously. Bradygastric slow waves are shown to propagate in the usual antegrade manner. Mayo Clinic Proceedings 1986 61, 205-210DOI: (10.1016/S0025-6196(12)61851-5) Copyright © 1986 Mayo Foundation for Medical Education and Research Terms and Conditions