Paper Information

Title:  THE EFFECT OF WATER IMMERSION STRESS ON LATE PHASE ISOLATED STOMACH FUNDUS STRIP MOTILITY OF RAT
Type: POSTER
Author(s): TAHER GOURABI Z.*,PAZOUKI TOROUDI H.R.,TAVAKOLI HOSSEINI N.
 
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Name of Seminar: IRANIAN CONGRESS OF PHYSIOLOGY AND PHARMACOLOGY
Type of Seminar:  CONGRESS
Sponsor:  PHYSIOLOGY AND PHARMACOLOGY SOCIETY, MASHHAD UNIVERSITY OF MEDICAL SCIENCE
Date:  2009Volume 19
 
 
Abstract: 

Introduction: Gastric ulcer is the result of imbalance between the effect of protective and destructive factors on gastric mucosal layer. There are so many proposed destructive factors including acid, bile, Nonsteroidal anti inflammatory drugs (NSAIDS) and increased gastric motility. In this study we examined the time course effect of water immersion stress on gastric motility.
Materials and Methods: Male wistar rats were immersed in 20-25oC water for 2 hours. After water immersion the rats were sacrificed on 30 min, 1 h, 6 h, 12 h and 24 h intervals and the stomachs were excised. Transverse strips of the fundus region were prepared and placed in organ bath containing modified Krebs solution perfused with carbogen gas (95% O2, 5% CO2) at 37oC. The contractile activity of the fundus strip was recorded using an isotonic transducer (preload 2g) on NarcoBioSystem physiograph. The amplitude and frequency of the spontaneous contractions werecompared to their relevant control groups using student t test ( p value < 0.05 ). In anotherseries of experiments the same protocol was applied and the stomachs were excised. Gastric mucosal ulceration was noted. Then the data was compared between the groups.
Results: No significant change was noticed between the water immersion stress groups and their relevant controls except in 24 h group. The amplitude of spontaneous contractions increased by 161%; Ulcer index was reduced by 80% 24h after water immersion stress.
Conclusion: In previous studies it has been shown that shortly after water immersion stress, gastric motility increases in live rats. In the isolated fundus strip model, it was noticed that the increase in contractile activity of the stomach occured only 24 hours after the water immersion stress. This may lead us to the conclusion that there are gastric as well as nongastric factors involve in water immersion induced gastric hypermotility. Nongastric factors (e.g. vagus nerve, systemic hormones and ...) act rapidly and its effect can be seen shortly after the stress in live animal models. But in isolated fundus strip model which is free from nongastric factors, a late increase in gastric motility can be seen. This may be due to the synthesis of cell made products like Immediately Early Genes (IEGs), Heat Shock Proteins (HSPs) and so on. The results indicate that there are no concordance between increased gastric contractions and mucosal ulceration. It seems that increased gastric contractions are not the cause of mucosal ulceration. Further work is needed to prove this theory.

 
Keyword(s): STOMACH, WATER IMMERSION STRESS, ISOLATED FUNDUS
 
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