The features of ultradian rhythms of the stomach and duodenum of rats under different time spans of blocking NO-synthase and the associated disturbance of regulatory mechanisms have been investigated. The functional relationship between changes in the МEA of stomach and duodenum, as well as the morphological status of the mucous membrane under disturbance of the nitric monoxide synthesis have been established. Each time blocking NO-ergic system caused an increase in motor performance index of the stomach and duodenum by 16.8 % and 42.4 % respectively (p < 0.05). On the sixth day of the NO deficiency, the motor index was noted to increase 1.5 times (p < 0.05), the duodenum rhythm imposed on stomach. It was accompanied by the duodenogastric reflux. On the twelfth day of NO deficit the reduction of the stomach and duodenum motor indices was noted, as compared with a control. It indicated exhaustion of adaptive-compensatory mechanisms. It is advisable to use of data obtained in the pathophysiology and in the medical practice.