Effects of unpredictability of shock on incidence of gastric lesions and heart rate in immobilized rats.
D000818:Animals; D003214:Conditioning, Classical; D003213:Conditioning, Psychological; D004597:Electroshock; D006339:Heart Rate; D007103:Immobilization; D008297:Male; D051381:Rats; D012054:Reinforcement, Psychology; D013276:Stomach Ulcer / Q000209:etiology*; D013312:Stress, Physiological / Q000150:complications