A 5-month-old white male developed gastric retention unrelieved by either pyloromyotomy or by gastrojejunostomy. The pattern of electrical activity in the wall of the stomach recorded at a third operation was consistent with an ectopic distal antral pacemaker generating electrical cycles (pacesetter potentials, action potentials, or control potentials) at a rapid frequency of 4.7 cycles per min (tachygastria). The gastric pressure increased from 1 cm H2O to only 5 cm H2O as the stomach was distended to 600 ml, with no further increase after 0.6 mg of urecholine given subcutaneously. Resection of the distal three-fourths of the stomach and gastrojejunostomy when the patient was 1 year old allowed him to resume oral intake without vomiting and with progressive weight gain. The circular smooth muscle cells of the corpus and antrum, when tested in vitro using intracellular electrodes, generated electrical cycles at rapid frequencies of 5 and 20 cycles per min, respectively. The plateau component of the spontaneous electrical cycles which regulates contractile activity, was small or absent in both corporal and antral cells, and the size of the plateau was not increased by pentagastrin or acetylcholine given at doses suprathreshold for healthy gastric smooth muscle. Our conclusion is that the decreased plateau size of the spontaneous electrical cycles generated by the gastric smooth muscle cells and the diminished sensitivity of the cells to appropriate contractile stimuli caused this patient's gastric retention.
ASJC Scopus subject areas