NICARDIPINE REDUCES THE LEVELS OF LEUKOTRIENE-C4 AND PROSTAGLANDIN-E2, FOLLOWING DIFFERENT ISCHEMIC PERIODS IN RAT-BRAIN TISSUE

Ischemic depolarization of nerve membranes is associated with a rapid influx of calcium into the cell, resulting in production of arachidonic acid (AA) metabolites. These metabolites, particularly leukotriene C4 (LTC4) have a very potent vasoconstrictor effect on cerebral arteries inducing vasogenic edema that may damage the ischemic penumbra. Calcium antagonists are assumed to prevent or reduce metabolic disturbances associated with ischemia. In this study, after developing an experimental animal model simulating the concept of the ischemic penumbra in the rat, the levels of LTC4 and prostaglandin E2 (PGE2) produced in the forebrain following different ischemic periods, such as 4th, 15th, 60th and 240th min were measured by a bioassay method, including 6 rats for each ischemic group. Then the effect of the 1-4 dihydropirine nicardipine (1 mg/kg) on these mediators was investigated by giving it to the rat 30 min before the development of the ischemic model in each corresponding group (n = 6). We showed that nicardipine significantly reduced the high levels of LTC4 and PGE2 in the 4th min and 4th h of cerebral ischemia (p < 0.005, p < 0.0005). So it may be concluded that institution of nicardipine may be helpful in protecting the ischemic penumbra during the early hours of cerebral ischemia

Effect of intraluminal temperature on human oesophageal motor function

Oesophageal motor activity is altered by bolus temperature. The effects of sustained cold or warm intraluminal temperature on oesophageal motility have not been documented in detail. Oesophageal manometry was performed in 11 normal subjects after intraluminal room, cold- and warm-water treatments. The intraluminal temperatures were 34.2 ± 0.8, 30.6 ± 1.7 and 39.7 ± 0.9°C respectively during room temperature, cold and warm applications. Low-temperature treatment prolonged the duration of lower oesophageal sphincter relaxation and the duration of oesophageal peristaltic contraction wave compared with the room temperature and warm treatments. Low temperature also attenuated the mean pressure slope of oesophageal contraction waves and resulted in an increased percentage of non-transmitted and simultaneous contractions. The effects of low-temperature application persisted as long as the intraluminal temperature remained constant and there was no adaptation. Cooling oesophageal lumen temperature alters oesophageal motor activity, and this effect is not adaptive

Ghrelin ameliorates pancreaticobiliary inflammation and associated remote organ injury in rats

The present study was designed to evaluate whether ghrelin could reduce organ injury and systemic inflammation induced by pancreaticobiliary obstruction. In Sprague-Dawley rats, either the bile duct (BDL) or common pancreaticobiliary duct (PBDL) was ligated or a sham operation was applied. BDL or PBDL rats received either ghrelin (10 ng/kg) or saline intraperitoneally immediately before the surgery and once a day until the rats were decapitated at 72 h. The pancreas, liver, lung and kidney were removed for the histological analysis, and for the determination of malondialdehyde (MDA), glutathione (GSH) levels and myeloperoxidase activity (MPO). MDA and MPO levels in all the tissues, which were elevated in PBDL group (p < 0.05-0.001), were reversed back to control levels in ghrelin-treated rats. In BDL group, elevations in hepatic MDA and MPO levels (p < 0.001) were also abolished by ghrelin treatment. In contrast to saline-treated group with severe pancreatic damage, ghrelin-treated rats demonstrated a moderate pancreatic and hepatic destruction accompanied with reduced pulmonary and renal damages. The results illustrate that ghrelin protects the hepatic and pancreatic tissues, as well as remote organs against oxidative injury, by a neutrophil-dependent mechanism. (c) 2006 Elsevier Ireland Ltd. All rights reserved

The effect of nitric oxide synthase blockade and indometacin on gastric emptying and gastric contractility

The aim of the present study was to investigate the effect of nitric oxide (NO) synthase inhibition on gastric emptying rate in conscious rats and on gastric muscle contractility. The involvement of NO was also investigated in indometacin-induced (25 mg/kg, s.c.) changes in gastric emptying rate and smooth muscle contractility. L-NAME (N-G-nitro-L-arginine methyl ester; 10 mg/kg, i.v.) inhibited the gastric emptying rate compared to controls and this effect was abolished by L-arginine (300 mg/kg, i.v.). Similarly, indometacin treatment led to a significant delay of gastric emptying rate with respect to vehicle-treated rats. Gastric longitudinal and circular muscle strips of L-NAME or indometacin-treated rats showed a reduction in contractile responses to carbachol. The results demonstrate that NO synthase blockade and indometacin treatment delay gastric emptying in conscious rats, concomitant with reduced responsiveness to carbachol, in vitro

Functional evidence for the involvement of GABA(A) receptors in cholecystokinin-induced ileal contraction

To determine the role of GABAergic neurotransmission in cholecystokinin octapeptide (CCK-8) induced contraction of the guinea pig ileal longitudinal muscle - myenteric plexus preparation, CCK(A) or CCK(B) receptors were protected by L 364,718 and L 365,260, respectively. GABA(A) receptors were protected with bicuculline and the remainder of the receptors were inactivated by N-ethylmaleimide. Following the specific treatments isometric contractions in response to CCK-8 (0.1 nM - 1.0 μM) were obtained. CCK(B) receptor protection alone abolished responses to CCK-8. Additional GABA(A)receptor protection restored the responses. CCK(A) receptor protection alone decreased contractile responses to CCK-8, and additional protection of GABA(A) receptors resulted in restoration of the contractile responses at high concentrations of CCK-8. The results suggest that the CCK(A) and CCK(B) receptors that mediate the contractile action of CCK differ with regard to GABAergic neurotransmission. CCK(B) receptors appear to be dependent upon intact GABAergic neurotransmission, whereas CCK(A) receptors partially utilize this pathway

Integration of Remote Sensing and GIS for Archaeological Investigations

The western hinterland of the modern city of Istanbul contains some of the most remarkable monuments of ancient and medieval hydraulic engineering dating from the fourth to the twelfth centuries AD, including lines of aqueduct channels and bridges extending up to 336 km to the west of the modern city. Until recently fieldwork has been limited and only within the last two decades have there been serious attempts to map the complexity of the monuments and water lines. The dense forest which covers much of the northern hills of Thrace is a major factor restricting fieldwork and survey, yet at the same time the woodland ensures the preservation of much of the system. Two previous studies of the water supply system have been able to identify the major spring sources, to map the line of the water supply channels and to record and locate over sixty bridges which are a key component of the system. However these studies have been constrained as they are not able to integrate adequately this survey data. The new research programme between Istanbul Technical University (ITU) and Edinburgh University commenced in 2007 and includes all existing GPS data and archaeological observations to be incorporated as part of a modern GIS combining the topographical and hydraulic information available from 1:25 000 digital maps with a wide range of high and medium resolution remotely sensed data. Further surface GPS based archaeological survey has been undertaken over the past two years and has been able document a significant number of the extant channels and bridges. Using high resolution IKONOS images and orthophotos it has been possible to create a textured land surface of forests and fields for the Thracian digital surface model (DSM) in which to situate the various monuments and channels of the water supply system. This digital resource is now capable of providing the basis for future archaeological documentation and analysis and two case studies are given. Integrated with multi-spectral data this gives the opportunity to view the system in its wider setting and also to identify major urban and landscape changes impacting on the long-term conservation and management of the ancient remains

Epidermal growth factor and bombesin act synergistically to support intestinal adaptation in rats with massive small bowel resection

Intestinal adaptation is the most important event in short bowel syndrome following a massive small bowel resection. Effects of various growth factors and their synergism have been well documented in intestinal adaptation. This study aimed to compare the effect of two different trophic agents, epidermal growth factor (EGF) and bombesin (BBS), on intestinal adaptation following massive intestinal resection. Sprague-Dawley male rats were assigned to one of four groups after a 75% small bowel resection. Either EGF (90 mu g/kg), BBS (10 mu g/kg), EGF+BBS, or bovine serum albumin (BSA) were injected subcutaneously three times a day. The animals were killed 10 days after the operation. Weight loss and morphologic parameters such as mucosal thickness, villus height, crypt depth, villus-to-crypt ratio, and muscularis propria height were measured. In the EGF+BBS group, mucosal thickness was found to be significantly increased compared with the other study groups (p < 0.05). Similarly, villus height was significantly increased only in the EGF+BBS group (p < 0.05). In the BBS group, both villus height and mucosal thickness showed a slight increase, but the values were not statistically significant compared with the vehicle-treated group. There were no significant differences in any of the remaining parameters between the groups. The results of this study indicate that the gut hormones EGF and BBS act synergistically in facilitating the adaptive response of the remnant ileum to massive intestinal resection

Oxidative organ damage in a rat model of thermal injury: the effect of cyclosporin A

Animal models of thermal trauma implicate oxygen radicals as a causative agent in local wound response, development of burn shock and distant organ injury. It has been proposed that the source of reactive oxygen metabolites could be neutrophils sequestered in systemic organs as a result of the systemic inflammatory reaction to a local burn insult. Recent studies have suggested that cyclosporin A (CsA), a potent immunosuppressive drug, may have effects on neutrophils by modulating the rate of their accumulation during acute inflammatory reactions. This study aimed to assess the role of neutrophils in the early and late phases of burn injury in rats with second-degree skin burn. We also aimed to determine whether CsA has protective effects on organs remote from the thermal injury. The results demonstrate that there is significant neutrophil accumulation in the gastric mucosa, liver and lung tissues during the early phase of a burn injury and that CsA failed to protect these organs. In conclusion, the data of this study suggest that neutrophil accumulation in liver, lung and gastric mucosa following burn injury may be involved in the pathogenesis of remote organ damage. The results also indicate that CsA failed to reduce the severity of damage in these organs, probably due to its own toxic effects