Search

Aim: The aim of this study is to investigate whether nitric oxide (NO)-mediated colonic motility was altered in rat irritable bowel syndrome (IBS) model, using different isoforms of NO-synthase (NOS) inhibitors. Materials and Methods: The animal model of IBS-like visceral hypersensitivity was induced by intra-colonic infusion of 0.5% acetic acid (AA) in saline once daily from postnatal days 8 to 21. Control animals received saline instead of AA. Experiments were performed at the end of 8 weeks. Distal colon tissues were resected and direct effects of different NOS inhibitors; N-omega-nitro-L-arginine methyl ester hydrochloride, (L-NAME), ARL-17477 dihydrochloride hydrate (ARL 17477), N-[[3-(Aminomethyl) phenyl] methyl]-ethanimidamidedihydrochloride (1400 W), and N5-(1-Iminoethyl)-L-ornithine dihydrochloride (L-NIO) were evaluated concentration-dependently in vitro tissue bath. Besides, morphology of both groups was assessed with hematoxylin and eosin (H and E) staining and the impact of NO antibodies was determined using the immunohistochemical method. Results: The mean pressure values of spontaneous contractions and KCL (80 mmol/L) responses of distal colonic segments were similar in normal and IBS rats. L-NAME and ARL-17477 significantly increased the mean pressure of spontaneous colonic contractions in normal rats versus own base values (P < 0.05), but this increase did not significantly different when compared to IBS rats. In H and E staining, there was no difference with regard to morphology between two groups. Neuronal NOS (nNOS) immunoreactivity was found to be significantly decreased in IBS when compared to control groups (P < 0.05). Conclusion: L-NAME and ARL-17477 mediated mean pressure values were found to be slightly decreased in IBS rats. These findings may be related to a decrease in nNOS level in IBS. [ABSTRACT FROM AUTHOR]

Background/Aims: Recent evidence supports a predominant role of β3-adrenoceptors at the end of pregnancy in myometrium. This study was designed to characterize the pharmacology of the selective β3-adrenoceptor agonist CL 316243 on oxytocin-induced myometrial contractions and the levels of cAMP and cGMP of myometrial strips isolated from term-pregnant rats. Methods: Myometrial strips were obtained from term-pregnant Wistar albino rats (n = 10), mounted in organ baths and tested for changes in isometric tension in response to CL 316243 (10-10-10-5M) on oxytocin-induced myometrial contractions. Effects of CL 316243 on cAMP and cGMP levels in isolated myometrial strips (n = 8) were evaluated by radioimmunoassay kits. We evaluated the effect of increasing concentrations of CL 316243 on myometrial contractions and on contractions of myometrial smooth muscle pretreated with metoprolol, ICI 118.551 and SR 59230A (β1-, β2-, β3-adrenoceptor antagonists, respectively, 10-6M). Results: The inhibition of the amplitude of oxytocin-induced contractions by CL 316243 were antagonized with SR 59230A (10-6M), but they were not changed by metoprolol (10-6M) or ICI 118.551 (10-6M). CL 316243 increased cAMP levels compared to the control group. CL 316243 increased cGMP levels, in the CL 316243 group more than in the control group, but this increase is less significant than cAMP levels. Conclusion: These results demonstrate that the inhibition of rat myometrial contractions with CL 316243 is mediated by β3-adrenoceptor subtype and increased cAMP and cGMP levels. Copyright © 2011 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Abstract: Background/Purpose: The aim of this study was to investigate the effect of peritonitis on spontaneous contractions of distal and proximal colon smooth muscle isolated from rats. Methods: Peritonitis was induced by cecal ligation and puncture in 8 rats. Another group of 8 rats underwent a sham operation and acted as controls. Twenty-four hours after the operation, the rats were killed; and their distal and proximal colon smooth muscle was excised and placed in circular muscle direction in a 10-mL organ bath. Changes in the amplitude and frequency of contractions were analyzed before and after the addition of antagonists. Results: Peritonitis induced the increase in the amplitude and frequency of spontaneous contractions. In both distal and proximal colon of the control group, the amplitude of spontaneous contractions was elevated by NG-nitro-l-arginine and tetradotoxin; but the frequency of spontaneous contractions was significantly elevated only in the presence of NG-nitro-l-arginine. In both distal and proximal colon of the peritonitis group, the enhanced amplitude and frequency were significantly decreased and returned to control values in the presence of celecoxib. Conclusions: Peritonitis induces the increase in the amplitude and frequency of spontaneous contractions of distal and proximal colon, which can be attributed to a loss of inhibitor nitrergic and other neural control or rise of cyclooxygenase-2 levels. [Copyright &y& Elsevier]

To the best of our knowledge this is the first case report describing exposure to varenicline, an a4ß2 nicotinic acetylcholine partial receptor agonist used for smoking cessation therapy in pregnancy. A 29-year-old multiparous woman with an unplanned pregnancy has used varenicline 2 mg/day unintentionally yet regularly 4 weeks from her last menstrual period. Fetal ultrasound performed at each trimester, detailed anomaly scan, and fetal echocardiography which were performed at the 22nd gestational week showed normal fetal growth with no malformations. The patient delivered a healthy baby at the 38th week of gestation with normal Apgar score and physical examination findings. Age-appropriate physical and neurological development of the child has been observed for 6 months. Although it is not possible to draw definitive conclusions, this case report may contribute to the current available limited data regarding the safety of varenicline use in pregnancy. [ABSTRACT FROM AUTHOR]