Changes in the myoelectric complex of the stomach and the small intestine under the influence of the intrinsic nervous system.

Chronic experiments have been carried out on dogs with implanted silver bipolar ball-shaped electrodes on the muscle wall of the stomach and of the duodenum after transthoracic truncus vagotomy. The appearance of incoordination in the rhythm of the slow potentials of the corpus and antrum is followed by an increase in the spike activity of the stomach and duodenum. The percentage of the spike activity increases, the active periods of the myoelectric complex become longer, with a decrease and even obliteration of the quiescent periods. These changes are most pronounced during the second post-vagotomy month, after which the spike activity gradually decreases and quiescent periods appear again. Nevertheless, at the end of the 6th month after the vagotomy, the spike activity has higher values than before the vagotomy. Chemical sympathectomy with 6-OHDA results in 100 per cent spike activity of the stomach and duodenum and complete absence of quiescent periods. It is concluded that the intrinsic nervous system is capable of organizing the phases of the myoelectric complex in the cases of absence of influence of the extrinsic nervous system.