Biomedical subjects

Firuzan Yildiz

Publications and source records attributed to Firuzan Yildiz.

3 recordsLinked to original sources

PubMed2003

Impaired gastric motility in the gastroesophageal reflux rat model: an in vitro study.

PURPOSE: The present study investigated the effects of acid and mixed reflux on the responsiveness of gastric smooth muscle in the gastroesophageal reflux (GER) rat model. MATERIAL AND METHODS: Three groups of rat were studied encompassing acid reflux, mixed reflux and sham operation. Acid reflux was induced by pyloric ligation (AR group) and mixed reflux was induced by jejunal ligation 1 cm distal to Treitz ligament (MR group). Similar surgical manipulations were carried out in the sham operated rats (SO group). Carbachol-, serotonin-, KCl-induced contractile response and nicotine-, sodium nitroprusside-, papaverine-induced relaxant response in isolated gastric fundus smooth muscle strips were determined using in vitro muscle technique 24 h after surgery. RESULTS: Isolated gastric fundus smooth muscle contractility to serotonin, carbachol or KCl was significantly reduced in the AR and MR groups with decreased Emax and pD(2) values compared with the SO group. Relaxant responses to nicotine was significantly increased in the AR and MR groups with increased Emax and pD(2) values compared with the SO group. Sodium nitroprusside and papaverine-induced-relaxant responses were similar in all of the groups and there was no change in agonist potency. CONCLUSION: The present study indicates that decreased contractile and increased nicotine-induced relaxant response of the gastric smooth muscle in the surgically created GER model. These findings suggest that impaired gastric smooth muscle reactivity at least in part may play a role in gastric dysmotility in GER.

Animals↗

PubMed2003

Development changes esophageal smooth muscle reactivity: an in vitro study.

This study was designed to determine if age related changes occur in esophageal smooth muscle reactivity in developing rats. Esophageal smooth muscle strips were obtained from three groups of rats: neonatal (1-3 days old), 1-month-old (30-35 days old) and young adults (4 months old). Esophageal smooth muscle reactivity was assessed in vitro by organ chamber experiments. Concentration-response curves were analyzed for differences in smooth muscle reactivity. Contractile response to cholinergic agonist carbachol increased in the neonatal group with increased maximum contraction compared to the other groups. However, there was no change in pD(2) value among the groups. Maximum contraction evoked by KCl was also significantly increased in the neonatal group compared to the adult group. Relaxation responses elicited by beta adrenoceptor agonist isoproterenol and 5-hydroxytryptamine (5-HT) receptor agonist serotonin were increased in the neonatal group with increased E(max) and pD(2) values compared to the other groups. The present study indicates that the neonatal esophageal smooth muscle responds to serotonergic, adrenergic and cholinergic agonists to a significantly greater degree than the adult esophageal smooth muscle.

Adrenergic beta-Agonists↗

PubMed2003

Esophagitis impairs esophageal smooth muscle reactivity in the rat model: an in vitro study.

The present study investigated how reflux-induced esophagitis affects the smooth muscle reactivity of the esophageal body. Two different esophagitis models were used: acid gastric and mixed duodenogastric reflux. All test animals apart from the controls developed gross and histologic evidence of esophagitis. Contractile (carbachol and KCI) and relaxant (isoproterenol) esophageal smooth muscle responses were significantly decreased in the presence of acid- and mixed reflux-induced esophagitis. Similar relaxant responses to serotonin and papaverine were found in the three groups. Our study demonstrated impaired esophageal smooth muscle reactivity when esophagitis was induced by acid or mixed reflux. These changes may correspond to the functional motor abnormalities of the esophagus seen in patients with reflux esophagitis.

Animals↗