Effect of Vitis Vinifera Leaf Extract on Ileum Mechanical Activity in Rat

Introduction: Vitis vinifera (grape) is from Vitaceae family and many researches have performed on its seed but not on leaf. It has been reported that Vitis vinifera leaf extract induces relaxation in rat uterus, aorta, trachea and vas deferens precontracted by KCl. According to these reports, the inhibitory effects have been evoked through the voltage dependent calcium channels blockade. The aim of present study was to investigate the effect of Vitis vinifera leaf hydroalcoholic extract (VHLE) on rat ileum contractions induced by KCl, acetylcholine (ACh) and barium chloride. Methods: Vitis vinifera leaf powder was extracted using manerated method by 70% alcohol for 72 h at ambient temperature and then solvent was evaporated. From Sprague Dawley rats (male and female) pieces of ileum (2cm) were isolated and placed in an organ bath (10ml) containing Tyrode’s solution gassed with oxygen. An isotonic transducer recorded contractions under 0.5g initial tension. The mean±SEM of changes in length (mm) or the percentages of length changes were calculated. Results: The results indicate that VHLE (0.25, 0.5, 1, 2 and 4mg/ml) reduces the ileum contractions induced by KCl (60mM) dose dependently (P<0.001). This inhibitory effect was unaffected by propranolol (1μM). VHLE (1mg/ml) also inhibited the ileum contractions induced by ACh (0.05 and 0.5μg/ml) P<0.001 and P<0.05 respectively. Ileum contraction induced by BaCl2 (4mM) was unaffected by VHLE (2mg/ml). Conclusion: In conclusion, it seems that VHLE inhibits ileum contractions via blocking the voltage dependent calcium channels. Ineffectiveness of propranolol on inhibitory effect of extract indicates that the adrenoceptors are not involved in this inhibitory effect. VHLE failed to relax ileum precontracted by BaCl2 probably because, BaCl2 increases intracellular calcium concentration via releasing calcium ions from intracellular pools that was not affected by VHLE

Effect of thyroid hormones on distension-induced gastric and Pepsin secretion in the stomach of rat

Abstract: Thyroid hormones are known to influence acid and pepsin secretion, though exact mechanism(s) are not fully understood. In this study distension-stimulated acid and pepsin secretion of hypo and hyperthyroid rats were compared with controls. Each group consisted of 8 N-mari rats from both sexes, weighing 246.6±9.2 g. Hypo and hyperthyroid states were induced by administration of methimazole (500 mg/l H2O) and thyroxine (200 µg/l H2O) respectively in drinking water. All animals were deprived of food, but not of water 24 hours before the experiments. After anesthesiation with sodium thiopental (50 mg/kg body weight, ip), tracheostomy and laparatomy, gastric secretions were collected through a cannula introduced via duodenum. Gastric distension was induced by Ringer solution in stomach (1.5cm³/100gr body weight). Acid secretions which were measured by automatic titrator in the hypothyroid, hyperthyroid and control groups were 8±0.2, 14.6±1.9 and 10.2±0.1 µmol/15min, respectively. Pepsin secretions were 4.4±0.5, 9.09±0.4 and 6.1±0.1 mg/15min in respective groups. Both series show statistically significant differences between control and the other two groups. The results from the measurements of TSH and T4 hormones show that increased or decreased thyroid function can significantly affect gastric distension-induced acid and pepsin secretion. Keywords: Thyroid hormones, Gastric acid secretion, Gastric pepsin secretion, Gastric distension, Ra