Person: YEGEN, ŞEVKET CUMHUR
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YEGEN
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ŞEVKET CUMHUR
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Publication Open Access The gastroprotective effect of obestatin on indomethacin-induced acute ulcer is mediated by a vagovagal mechanism(AKADEMIAI KIADO ZRT, 2020-06) YEGEN, BERRAK; Sen, Leyla Semiha; Kumral, Zarife Nigar Ozdemir; Memi, Gulsun; Ercan, Feriha; Yegen, Berrak C.; Yegen, CumhurIn order to investigate the role of the vagus nerve in the possible gastroprotective effect of obestatin on the indomethacin-induced acute oxidative gastric injury, Sprague-Dawley rats of both sexes were injected subcutaneously with indomethacin (25 mg/kg, 5% NaHCO3) followed by obestatin (10, 30 or 100 mu g/kg). In other sets of rats, surgical vagotomy (Vx) or selective degeneration of vagal afferent fibers by perivagal capsaicin was performed before the injections of indomethacin or indomethacin + obestatin (30 mu g/kg). Gastric serosal blood flow was measured, and 4 h after ulcer induction gastric tissue samples were taken for histological and biochemical assays. Obestatin reduced the severity of indomethacin-induced acute ulcer via the reversal of reactive hyperemia, by inhibiting ulcer-induced neutrophil infiltration and lipid peroxidation along with the replenishment of glutathione (GSH) stores, whereas Vx abolished the inhibitory effect of obestatin on blood flow and lipid peroxidation, and worsened the severity of ulcer. On the other hand, serosal blood flow was even amplified by the selective denervation of the capsaicin-sensitive vagal afferent fibers, but obestatin-induced reduction in ulcer severity was not altered. In conclusion, the gastroprotective effect of obestatin on indomethacin-induced ulcer appears to involve the activation of the vagovagal pathway.Publication Metadata only Enterogastric brake in rats with segmental bowel resection: Role of capsaicin-sensitive nerves(WILEY, 2002) YEGEN, BERRAK; Topcu, T; Gulpinar, MA; Isman, CA; Yegen, BC; Yegen, C1. Unabsorbed nutrients in the distal gut inhibit upper gastrointestinal motility. 2. The aim of the present study was to investigate changes in gastric motility following segmental resections and to evaluate the role of capsaicin-sensitive afferent neurons that may be responsible for these changes. 3. Wistar albino rats of both sexes (200-250 g) were used. Under aseptic conditions and anaesthesia (100 mg/kg ketamine), a baby-feeding tube was placed distal to the resection in either the ileum or caecum for intraluminal perfusion of saline or 20% lipid. In one group of rats, capsaicin was perfused (0.6%) for afferent denervation. One group of rats underwent jejunal and ileal resections with end-to-end anastomosis of the remaining segments and were cannulated distal to these anastomosis. Ten days after the surgery, the percentage gastric emptying of a solid meal was calculated. 4. Intra-ileal (18%) and intracaecal (34%) lipid perfusions delayed gastric emptying compared with groups perfused with saline (54% and 74%, respectively; P < 0.001 and P < 0.01). The delay in gastric emptying by ileal perfusion was significantly greater than that following caecal perfusion (P < 0.05). With both resections, gastric emptying was delayed compared with sham groups (P < 0.05-0.01). Local administration of capsaicin abolished the inhibitory effect of lipid on gastric emptying in healthy intact rats and in the jejunal-resection group, whereas a partial reversal was seen in the ileal-resection group. 5. In conclusion, the present data demonstrate that in both healthy intact rat groups and in short bowel groups, capsaicin-sensitive extrinsic neurons participate in 'brake' mechanisms of the distal gut.