Changes in the character of electrical and contractile activities of isolated fundus with functional loading...

A 2/3 resection of the stomach with restoration of the continuity by a Billroth I anastomosis was carried out on dogs and cats. At different times, following surgery, electrical activity of the fundus wall was recorded in vitro using pressure electrodes. Contractile activity of isolated fundus strips from these animals was also studied. Electrical activity of the isolated fundus of an intact (non resected) stomach was characterized by irregular low-amplitude slow waves of a sinusoidal type with a frequency of about 2 cpm, and in rare cases of about 4 cpm. Mechanical activity of the non-resected fundus was mainly tonic. In the isolated resected stomach (gastric remnant), a regular slow wave rhythm of about 4 cpm was established. Slow waves gradually increased in amplitude, achieving a plateau potential configuration. They were associated with low-amplitude contractions. The mechanical activity of the fundus after resection became mainly phasic. For the early establishment of this rhythm and configuration it was important to retain part of the pacemaker area of the stomach in the gastric remnant. In this case, electrical and contractile activities of the fundus became similar to those of the corpus and antrum, probably as a result of the functional loading of the fundus after resection.