Inhibitory effects of various types of stress on gastric tone and gastric myoelectrical activity in dogs

Objective. Stress impairs gastrointestinal motility, causing, for example, delayed gastric emptying and altered intestinal transit. However, little is known about the effect of various stress factors on gastric tone and gastric myoelectrical activity (GMA). The aim of this study was to assess the effect of various kinds of stress on gastric tone and GMA in a canine model. Material and methods. Six dogs, implanted with a gastric cannula and one pair of gastric seromuscular electrodes, were studied. Three kinds of stress (visual, thermal, or audio stimulation) were applied in separate sessions. GMA and gastric tone were recorded for 30 min at baseline and 30 min during stress. Results. Visual stress (blinding) did not alter gastric tone or GMA; cold stress (ice water) and audio stress (loud noise) significantly inhibited gastric tone: gastric volume was increased from 107.213.5 ml at baseline to 135.623.8 ml with cold stress (p=0.041), and from 106.45.7 ml at baseline to 159.215.1 ml with audio stress (p=0.007). Although the dominant frequency or power of gastric slow waves was not altered, the percentage of normal gastric slow waves was markedly reduced from 98.30.8 to 87.53.7 with cold stress and from 90.23.3 to 80.62.9 with audio stress (p0.05). Conclusions. Cold- and audio stress inhibit gastric tone and impair gastric slow waves, whereas visual stress does not seem to have such effects. These findings will help to increase our understanding of gastrointestinal motor disorders related to stress.