Sigma receptor ligands haloperidol and ifenprodil attenuate hypoxia induced dopamine release in rat striatum.

OBJECTIVE: We aimed to investigate the hypothesis that sigma receptor ligands, haloperidol and ifenprodil, attenuate hypoxia-induced striatal dopamine release in vitro and determine the possible mechanisms. METHODS: Extracellular concentrations of dopamine were measured using acute brain slices method under hypoxic, aglycemic and ischemic conditions. Sigma receptor ligands haloperidol and ifenprodil attenuate striatal dopamine release induced by hypoxia in contrast to aglycemia and ischemia. To determine the possible contribution of glutamatergic system on this effect, we compared the effect of NMDA receptor antagonist MK-801 and haloperidol in hypoxia induced by Na-K-ATPaz enzyme inhibitor ouabain. Also, we compared the effect of dopamine uptake blocker nomifensine and haloperidol to determine the role of dopamine transporter on this effect. RESULTS: Haloperidol and nomifensine almost completely abolish ouabain-induced dopamine release unlike MK-801. Different effects of sigma ligands and glutamate receptor antagonists on the hypoxia and ouabain induced dopamine release show that glutamate receptor blockade is partial involved in inhibitory effect of sigma ligand on dopamine release under hypoxic conditions. Similar effect of dopamine uptake blocker nomifensine and sigma receptor ligand haloperidol on ouabain induced dopamine release supports the possibility that inhibition of reverse dopamine transport by sigma ligands might be involved in their protective effect. CONCLUSIONS: Data in this study suggest that sigma ligands may be a new therapeutic intervention for the management of hypoxic conditions.

The protective effect of L-carnitine on hepatic ischemia-reperfusion injury in rats.

BACKGROUND/AIMS: Ischemia-reperfusion injury may occur during liver transplantation and remains a serious concern in clinical practice. This study was designed to study the potential benefit of L-carnitine on experimental warm hepatic ischemia-reperfusion injury in rats. MATERIALS AND METHODS: Forty-five male Wistar Albino rats were divided into three groups; Group 1 sham-operation without ischemia-reperfusion (n=15); Group 2, ischemia-reperfusion (n=15); and Group 3, which was administered L-carnitine (200 mg/kg, intraperitoneal, for 4 days) prior to ischemia-reperfusion (n=15). The study animals were then sacrificed to obtain hepatic tissue and serum samples. Tissue levels of malondialdehyde and reduced glutathione and serum levels for aspartate aminotransferase, alanine aminotransferase and lactate dehydrogenase were assessed. RESULTS: Mean aspartate aminotransferase levels were significantly higher in Group 2 (405.2 U/L) when compared to Groups 1 (137.1 U/L) and 3 (267.6 U/L). Mean alanine aminotransferase levels were significantly higher in Group 2 (257.1 U/L) when compared to Groups 1 (37.2 U/L), and 3 (118.1 U/L) (p< 0.001 for each). Mean lactate dehydrogenase levels were significantly higher in Group 2 (2943.8 U/L) when compared to Groups 1 (1496.5 U/L), and 3 (2185.3U/L) (p < 0.001 for each). Mean malondialdehyde levels were significantly higher in Group 2 (54.3 nmol/g) compared to Groups 1 (41.0 nmol/g) and 3 (42.1 nmol/g) (p < 0.001 for each). Mean reduced glutathione levels were significantly lower in Group 2 (5.9 nmol/mg) and Group 3 (7.4 nmol/mg) compared to Group 1 (9.1 nmol/mg) (p < 0.001 for each). CONCLUSIONS: In conclusion, our data supports a protective effect of L-carnitine against oxidative damage in hepatic ischemia-reperfusion injury in rats. This is evidenced by improvement of the antioxidant defense system and lipid peroxidation levels.

Effects of pioglitazone and retinoic acid in a rotenone model of Parkinson's disease.

Parkinson's disease (PD) is a late-onset, progressive and neurodegenerative disorder of unknown etiology. Besides the other therapeutic approaches, new drug options in pharmacotherapy of PD are important. The aim of the present study was to investigate the effects of pioglitazone and retinoic acid, antioxidant and neuroprotective agents, on rotenone-induced model of PD in rats. Adult male Wistar rats (260-373 g) were subjects. Rotenone (2.5mg/kg, sc) was injected to rats for 70 days. At the end of rotenone administration, rats were treated with pioglitazone (10mg/kg, ip) and retinoic acid (1mg/kg, ip) or vehicles for 15 days. Then, rats were tested for evaluation of Parkinson signs by measurement of locomotor activity. In addition, dopamine levels were detected in striatum, hippocampus and hypothalamus in individual groups of control, rotenone and pioglitazone or retinoic acid-treated rats. Rotenone significantly reduced locomotor activity of the rats. It also significantly reduced dopamine levels in striatum and hippocampus, but not hypothalamus. Pioglitazone and retinoic acid reversed in reduction of locomotor activity significantly. Pioglitazone, but not retinoic acid, significantly reversed the reduced striatal dopamine level. Both drugs were ineffective on reduced levels of dopamine in hippocampus. Our results suggest that pioglitazone and retinoic acid have some beneficial effects on rotenone-induced model of PD in rats. Pioglitazone seems to be more effective than retinoic acid. These agents may be helpful for preventing or controlling of some signs of PD.

Mechanism of S100b release from rat cortical slices determined under basal and stimulated conditions.

Incubation of rat cortical slices in a medium that was not containing oxygen and glucose (oxygen-glucose deprivation, OGD) caused a 200% increase in the release of S100B. However, when slices were transferred to a medium containing oxygen and glucose (reoxygenation conditions, or REO), S100B release reached 500% of its control value. Neither inhibition of nitric oxide (NO) synthase by L-NAME nor addition of the NO donors sodium nitroprussid (SNP) or hydroxylamine (HA) to the medium altered basal S100B release. Similarly, the presence of SNP, HA or NO precursor L: -arginine in the medium, or inhibition of NO synthase by L-NAME also failed to alter OGD- and REO-induced S100B outputs. Moreover, individual inhibition of PKC, PLA(2) or PLC all failed to attenuate the S100B release determined under control condition or enhanced by either OGD or REO. Blockade of calcium channels with verapamil, chelating the Ca(+2) ions with BAPTA or blockade of sodium channels with tetrodotoxin (TTX) did not alter OGD- and REO-induced S100B release. In contrast to the pharmacologic manipulations mentioned above, glutamate and alpha-ketoglutarate added at high concentrations to the medium prevented both OGD- and REO-induced S100B outputs. These results indicate that neither NO nor the activation of PKC, PLA(2) or PLC seem to be involved in basal or OGD- and REO-induced S100B outputs. Additionally, calcium and sodium currents that are sensitive to verapamil and TTX, respectively, are unlikely to contribute to the enhanced S100B release observed under these conditions.

Resveratrol protects rat striatal slices against anoxia-induced dopamine release.

Incubation of rat striatal slices in anoxic medium caused significant alterations in dopamine (DA) and 3,4-dihydroxyphenylacetic acid (DOPAC) outputs; while DA release increased several times, 50% decline in DOPAC output was observed under this condition. Tissue ATP level, on the other hand, was decreased 40% by anoxia. Presence of resveratrol in the medium decreased anoxia-induced DA release in a concentration-dependent manner. Enhanced DA output, however, was declined slightly by epicatechine and catechine, and not altered significantly by morin hydrate and quercetin dehydrate which are other penolic compounds present in the red wine. In contrary to DA output, anoxia-induced decline in tissue ATP level was not ameliorated by resveratrol. In addition to anoxia, resveratrol, as observed with DA uptake blocker nomifensine, also reduced DA release stimulated by ouabain. Efficiencies of both resveratrol and nomifensine to attenuate ouabain-induced DA output, however, were closely dependent on ouabain concentration in the medium. These results indicate that some phenolic compounds, particularly resveratrol decrease anoxia-induced DA output and appear promising agents to improve the alterations occurred under anoxic-ischemic conditions.

Low eradication rate of Helicobacter pylori with triple 7-14 days and quadriple therapy in Turkey.

AIM: The eradication rate of Helicobacter pylori (H pylori) shows variation among countries and regimens of treatment. We aimed to study the eradication rates of different regimens in our region and some factors affecting the rate of eradication. METHODS: One hundred and sixty-four H pylori positive patients (68 males, 96 females; mean age: 48+/-12 years) with duodenal or gastric ulcer without a smoking history were included in the study. The patients were divided into three groups according to the treatment regimens. Omeprazole 20 mg, clarithromycin 500 mg, amoxicillin 1 g were given twice daily for 1 week (Group I) and 2 weeks (Group II). Patients in Group III received bismuth subsitrate 300 mg, tetracyline 500 mg and metronidazole 500 mg four times daily in addition to Omeprazole 20 mg twice daily. Two biopsies each before and after treatment were obtained from antrum and corpus, and histopathologically evaluated. Eradication was assumed to be successful if no H pylorus was detected from four biopsy specimens taken after treatment. The effects of factors like age, sex, H pylori density on antrum and corpus before treatment, the total H pylori density, and the inflammation scores on the rate of H pylori eradication were evaluated. RESULTS: The overall eradication rate was 42%. The rates in groups II and III were statistically higher than that in group I (P<0.05). The rates of eradication were 24.5%, 40.7% and 61.5% in groups I, II and III, respectively. The eradication rate was negatively related to either corpus H pylori density or total H pylori density (P<0.05). The median age was older in the group in which the eradication failed in comparison to that with successful eradication (55 yr vs 39 yr, P<0.001). No correlation between sex and H pylori eradication was found. CONCLUSION: Our rates of eradication were significantly lower when compared to those reported in literature. We believe that advanced age and high H pylori density are negative predictive factors for the rate of H pylori eradication.

Percutaneous introduction of a snare for removal of migrated biliary stents.

This report describes two cases in which proximally migrated Amsterdam-type biliary stents were extracted using transhepatic snare introduction into the bile ducts. In one case, the migrated stent was removed transhepatically via a percutaneous approach, and in the other a combination transhepatic-endoscopic extraction was successful. No complications were encountered. Percutaneous introduction of snare via transhepatic route offers a good alternative to surgery for removal of migrated biliary stents.

Gastroesophageal reflux disease in chronic renal failure patients with upper GI symptoms: multivariate analysis of pathogenetic factors.

OBJECTIVE: The association between gastroesophageal reflux disease and end-stage renal disease remains unclear. We aimed to assess the prevalence of gastroesophageal reflux disease and also to identify possible pathogenetic factors in the development of reflux in symptomatic end-stage renal disease patients. METHODS: The study involved 42 end-stage renal disease patients with upper GI symptoms (group I) and 46 age- and sex-matched controls who did not have renal disease but had the same symptoms (group II). Endoscopy, endoscopic biopsies, and 24-h esophageal pH studies were used to diagnose gastroesophageal reflux disease. Subjects were also investigated for Helicobacter pylori gastritis and GI amyloidosis. RESULTS: The prevalences of gastroesophageal reflux disease in the two groups were similar (81% vs 84.8%, p = 0.423). The prevalence of H. pylori infection was significantly lower in group I than in group II (38.1% vs 67.4%, p = 0.01). There were II cases of GI amyloidosis in group I. Multivariate logistic regression analysis in group I showed that GI amyloidosis (OR = 7.28, 95% CI = 1.13-46.93), chronic ambulatory peritoneal dialysis treatment (OR = 5.54, 95% CI = 1.01-30.43), and absence of H. pylori infection (OR = 3.75, 95% CI = 1.01-13.9) were significantly associated with reflux esophagitis. CONCLUSIONS: Upper GI symptoms are important in predicting gastroesophageal reflux disease in end-stage renal disease patients. Chronic ambulatory peritoneal dialysis, GI amyloidosis, and absence of H. pylori infection seem to be risk factors for the development of gastroesophageal reflux disease in end-stage renal disease patients.