[Electromechanical contractive activity of the stomach and duodenum of conscious dogs]

Studies were conducted in three conscious dogs implanted with electrodes and force transducers on the gastric antrum and duodenum. During the period of development of the interdigestive myoelectric complex (IMC) or the interdigestive contractions, intervals of development and amplitudes of the basic electric rhythm (BER) in the antrum varied markedly in contrast with those during the period of motor quiescence. In the antrum and duodenum, the frequency of BER decreased during IMC, and transiently increased after the end of IMC. After feeding, action potentials were superimposed on every BER of the antrum which occurred regularily, and a contraction accompanied each group of action potentials. While, in the duodenum, the percentage of BER's with action potentials was about 40%. The frequency of BER decreased in the antrum and increased in the duodenum compared with that before feeding. Wave form of action potentials and/or amplitude of contractions varied and the maximum amplitude of the contractions in the digestive state never exceeded that of the interdigestive contractions. Ratio of BER frequency of the duodenum to that of the antrum was 3.7-4.4 during the motor quiescence, while, during the period of development of the interdigestive contractions and the contractions in fed state, it was relatively high (4.3-4.6). Coinciding with the strong contractions among the interdigestive contractions of the antrum, diminution of the high-amplitude contractions in the duodenum was observed. On the other hand, in the digestive state, cyclic occurrence of a contraction in the antrum approximately corresponded in time with occurrence of contractions in the duodenum.