The role of the cholinergic system in the memory-protecting effects of metformin in a model of scopolamine-induced memory impairment in aged rats.

PURPOSE: As the elderly population grows, the prevalence of dementia is also rapidly increasing worldwide. Metformin, an antidiabetic drug, has been shown to have ameliorative effects on impaired cognitive functions in experimental models. However, studies have generally used young animals. Additionally, although it has a major role in Alzheimer's disease (AD) and memory, literature information about the effects of metformin on the cholinergic system is limited. In this study, we investigated the effects of metformin on memory in a model of scopolamine-induced memory impairment in aged rats. We also examined the effects of metformin on the cholinergic system, which is very important in cognitive functions. METHODS: Metformin was administered orally to male Wistar rats (20-22 months old) at 100 mg/kg/day for three weeks. Morris water maze (MWM) tests were performed to assess spatial memory. Before the probe test of the MWM test, scopolamine was injected intraperitoneally at a dose of 1 mg/kg. After testing, animals were sacrificed, whole brains were removed, and hippocampus samples were separated for biochemical analysis. RESULTS: Impaired memory associated with scopolamine administration was reversed by metformin. In addition, metformin administration ameliorated scopolamine-induced changes in acetylcholine (ACh) levels, acetylcholinesterase (AChE), butyrylcholinesterase (BuChE), and choline acetyltransferase (ChAT) activity. CONCLUSION: Our results show that metformin may have protective effects in a scopolamine-induced memory impairment model in aged animals by improving cholinergic function. Metformin shows promise in preventing dementia with its dual cholinesterase inhibition and ChAT activation effect.

An Evaluation of the Effectiveness of Melatonin and n-Acetylcysteine in Cerebral Ischemia-Reperfusion Injury in Adult Rats.

Background and Objectives: The purpose of this study was to apply histopathological and immunohistochemical methods to compare the protective efficacy of melatonin and N-acetylcysteine (NAC) application in rats with experimental brain ischemia/reperfusion (I/R) injury induced through occlusion of the middle cerebral artery (MCA), and to evaluate the protective effect of their combined use. Materials and Methods: Forty-one young adult male Wistar albino rats were divided into five groups-control (n = 8), I/R group (n = 8), melatonin (n = 8), NAC (n = 8), and melatonin + NAC (n = 9). Results: All scores differed between the groups, apart from vascular congestion (p < 0.05). At two-way comparisons, all histological scores were significantly higher in the I/R group than in the control group (p < 0.05). No change occurred in the vascular congestion scores with the administration of melatonin, although decreases were determined in all other scores. These decreases were statistically significant for cellular eosinophilic pyknotic degeneration, vacuolization, and edema (p < 0.05). All histopathological scores in the group administered NAC together with melatonin were significantly lower than in the I/R group (p < 0.05). Conclusions: The combined use of NAC and melatonin, the neuroprotective efficacy of which on histopathological parameters is shown in this study, now needs to be supported by further research.

Neurological Symptoms That May Represent a Warning in Terms of Diagnosis and Treatment in a Group of Children and Adolescents with Vitamin D Deficiency.

AIM: This research was intended to evaluate the clinical and laboratory findings of children presenting to our pediatric neurology clinic with symptoms potentially linked to vitamin D deficiency and with low vitamin D levels and the distribution of those findings by sex, age groups, and vitamin D levels. METHODS: This retrospective study involved patients presenting to our clinic with symptoms potentially associated with vitamin D deficiency and low serum concentrations of 25 OH vitamin D (25 OH D) (<75 nmol/L, 30 µg/mL). Patients' movement disorders and central nervous system-related symptoms at the time of presentation and serum 25 OH D, calcium (Ca), phosphorus (P), and magnesium (Mg) levels were recorded and evaluated in terms of age, sex, and vitamin D levels. RESULTS: Eight hundred twenty-two cases of vitamin D deficiency were included in the study, 50.2% (n = 413) boys and 49.8% (n = 409) girls. Although cases of vitamin D deficiency were present across all the age groups between 1 and 18, they were most common in the 5-14 age range (n = 372, 45.3%). Movement disorders were observed in 14.6% (n = 120) of our cases, and neurological findings associated with the central nervous system were observed in 52.6% (n = 432). The most common accompanying movement in our cases was difficulty remaining in balance (n = 42, 35%), while the most frequent accompanying central nervous system finding was vertigo (n = 99, 22.92%). Other movement disorders encountered included limb shaking (n = 32, 26.7%), abnormal posture (n = 20, 16.67%), easy falling (n = 16, 13.33%), body rigidity (n = 15, 12.5%), and hand clenching (n = 5, 4.17%). Other frequently encountered neurological findings were headache (n = 88, 20.37%), epileptic seizures (n = 83, 19.21%), fainting (n = 58, 13.43%), developmental delay (n = 41, 9.49%), febrile seizures (n = 33, 7.64%), and numbness in the fingers (n = 20, 4.63%). Other neurological findings were sleep disorders (n = 10, 2.31%), nightmares (n = 8, 1.85%), pain in the extremities (n = 7, 1.62%), and sweating and frailty (n = 4, 0.93% for both). Ca, P, and Mg levels were lower in cases with vitamin D levels < 12 µg/mL. The prevalences of both movement disorders and central nervous system findings varied according to age groups, sex, and vitamin D levels. CONCLUSIONS: Our study results show that vitamin D deficiency can present with different neurological findings and that these may vary according to age group, sex, and vitamin D levels. Clinicians must take particular care in pediatric cases with neurological findings in terms of the early diagnosis and treatment of vitamin D deficiency.

Effect of levetiracetam therapy on electrocardiographic parameters.

AIM: The purpose of this study was to compare the electrocardiographic parameters before and at the sixth month of treatment of patients diagnosed with epilepsy and who were started on levetiracetam therapy. METHODS: The files of 30 patients diagnosed with epilepsy and on levetiracetam therapy were examined in this study. Clinical findings, electroencephalography (EEG), cranial magnetic resonance imaging (MRI) and electrocardiography (ECG) data before and at the sixth month of treatment were recorded. RESULTS: The patients' mean age was 10.93 ± 3.74 (4-17) years; 16 (53.33%) patients were boys. In total, 13 (43.3%) were found to experience focal seizures, and 17 (56.7%) generalized epilepsy-type seizures. Comparison of the ECG parameters (PR interval, QTc, QT interval, and QRS duration) revealed a shortening in the PR interval and QTc values at the sixth month of treatment, although the changes were not statistically significant. No significant differences in terms of gender and epilepsy types were observed between the ECG parameters before treatment and at the sixth month (p > 0.05). CONCLUSION: In this study, levetiracetam was found to have no effect on ECG parameters.

Antiinflammatory effects of adalimumab, tocilizumab, and steroid on lipopolysaccharide-induced lung injury.

BACKGROUND: Acute lung injury (ALI) is a major cause of death in the intensive care unit. Lipopolysaccharide (LPS) induced lung injury is the most widely used experimental ALI model and provides opportunities for new targeting therapy. In this study, we investigated the effects of tocilizumab, adalimumab, and methylprednisolone in LPS-induced acute lung injury. METHODS: Lung injury was established by intratracheal instillation of LPS. The rats were randomly divided into six groups: LPS, control, and treatment groups (adalimumab, tocilizumab, methylprednisolone, adalimumab + tocilizumab). Bronchoalveolar lavage (BAL) and lung tissues were collected at 48 h and 96 h following LPS administration from each group. For histological analysis, hematoxylin-eosin (H&E) staining was performed. The sections were obtained for immunohistochemical analysis. IL-6 and TNF-alpha immunoreactivity were measured. RESULTS: Intratracheal LPS application resulted in inflammatory cell infiltration of interstitial and alveolar spaces and thickening of the alveolar wall. All treatment groups showed significantly amelioration compared to LPS at 48 h. Interestingly, adalimumab and adalimumab + tocilizumab groups showed a significant amelioration of the lung histoarchitecture, compared to the prednisolone group at 96 h (p = 0.028, p = 0.025, respectively). Compared to the control group, LPS stimulation resulted in a significant increase in IL-6 and TNF-alpha immunoreactivity (p < 0.001). IL-6 and TNF-alpha expression were markedly reduced in all treatment groups at 48 h but the reduction was greater in the adalimumab and tocilizumab group than in the steroid. Administration with adalimumab and/or tocilizumab effectively decreased expression of TNF-alpha (p = 0.001) and IL-6 (p < 0.001) at 96 h, but prednisolone did not exert an effective decrease (p > 0.05). DISCUSSION: Adalimumab and/or tocilizumab significantly reduce the release of proinflammatory cytokines and improve the tissue inflammation in the experimental model of ALI. Our results suggest that adalimumab and/or tocilizumab have a more potent antiinflammatory effect on lung injury than the steroid.

Effect of certain non-steroidal anti-inflammatory drugs on the paraoxonase 2 (PON2) in human monocytic cell line U937.

The paraoxonase gene family in humans consists of three members as PON1, PON2 and PON3. PON2 can be expressed in several tissues; however, it is not released from the cells in those tissues. PON2 is also expressed in macrophages. Firstly, the commonly used NSAIDs diclofenac sodium and tenoxicam were applied on U937 cell line, the in vitro human monocyte cell line. Than PON2 specific Lactonase activity and paraoxonase family specific arylesterase were determined. Use of Diclofenac sodium in 0.845 mM dose during 6-12 h of incubation and Tenoxicam in 0.74 mM dose during 6 h of incubation resulted in a significant decline in the lactonase activity. Diclofenac sodium didn't make any change in the arylesterase activity. On the other hand, tenoxicam decreased arylesterase activity during the use of 12 h, in 0.74 mM and 1.48 mM dose.

Single dose varenicline may trigger epileptic activity.

Varenicline is a new drug for smoking cessation, and its effect on epilepsy is not clear. The aim of this study was to investigate whether different doses of varenicline cause epileptic activity. Forty rats were randomly assigned to the following eight groups: control, saline, and 0.025, 0.04, 0.1, 0.5, 1, and 2 mg kg(-1) varenicline (single dose, i.p.). EEGs were recorded before the varenicline injection and during the following 240 min. While epileptic discharges were observed on the EEGs of the rats in all of the varenicline-treated groups, motor findings of epileptic seizure were not observed in some rats in these groups except the 1 and 2 mg kg(-1) groups. These findings indicate that different single doses of varenicline cause epileptic activity in rats.

Protective effect of 2-aminoethyl diphenylborinate on acute ischemia-reperfusion injury in the rat kidney.

BACKGROUND: To investigate the protective effect of 2-aminoethyl diphenylborinate (2-APB) against ischemia-reperfusion (I/R) injury in the rat kidney by an experimental study. MATERIALS AND METHODS: Thirty male Sprague-Dawley rats were randomly divided into the following three groups: (1) sham group, (2) I/R group, and (3) I/R + 2-APB group. Renal I/R injury was induced by clamping the left renal pedicle for 45 min after right nephrectomy, followed by 3 h of reperfusion. The therapeutic agent 2-APB was administered intravenously at a dose of 2 mg/kg 10 min before renal ischemia. Glutathione, superoxide dismutase, total antioxidant capacity, malondialdehyde, tumor necrosis factor α, interleukin 6, aspartate aminotransferase, alanine aminotransferase, and creatinine levels were measured from blood samples, and the rats were sacrificed subsequently. Tissue samples were scored histopathologically. Visualization of apoptotic cells was performed using the terminal deoxynucleotidyl transferase dUTP nick end labeling staining method. RESULTS: 2-APB significantly reduced serum malondialdehyde, tumor necrosis factor α, interleukin 6, aspartate aminotransferase, alanine aminotransferase, and creatinine levels in the I/R injury group. However, glutathione, superoxide dismutase, and total antioxidant capacity levels increased significantly. Histopathologic scores were significantly better and the rate of apoptosis was lower in the 2-APB group. CONCLUSIONS: 2-APB reduces oxidative stress and damage caused by renal I/R injury. The results of this study demonstrate that 2-APB can be used as an effective agent against I/R injury in the kidney.

Effects of boric acid and 2-aminoethoxydiphenyl borate on necrotizing enterocolitis.

OBJECTIVE: The aim was to study the effects of boric acid (BA) and 2-aminoethoxydiphenyl borate (2-APB) on oxidative stress and inflammation in an experimental necrotizing enterocolitis (NEC) rat model. METHODS: Experimental NEC was induced in 40 newborn Sprague-Dawley rats by asphyxia and hypothermia applied in 3 consecutive days. Rats were subdivided into 4 subgroups as NEC, NEC+BA, NEC+2-APB, and controls. BA and 2-APB were applied daily before the procedure. Serum total antioxidant status, superoxide dismutase (SOD), tumor necrosis factor (TNF)-α, interleukin (IL)-6, and erythrocyte glutathione (GSH) levels were measured. Pathological changes for NEC in intestinal architecture were evaluated by a grading system. RESULTS: Pretreatment with BA and 2-APB resulted in a decrease in NEC incidence. In all of the NEC groups, decreased serum levels of GSH and SOD were measured. Boron limited GSH consumption but had no effect on SOD levels. Total antioxidant status levels were not statistically different among groups. In our experimental NEC model, BA, but not 2-APB, prevented the increase of TNF-α. Pretreatment with BA and 2-APB downregulated the activity levels of IL-6 in NEC. CONCLUSIONS: In the experimental NEC model, BA and 2-APB partly prevent NEC formation, modulate the oxidative stress parameters, bring a significant decrease in GSH consumption, and enhance the antioxidant defense mechanism, but have no effect on total antioxidant status. BA inhibits the hypoxia and hypothermia-induced increase in both IL-6 and TNF-a, but 2-APB only in IL-6. Boron may be beneficial in preventing NEC.

Esophageal and gastric smooth muscle activity after carbon dioxide pneumoperitoneum.

BACKGROUND: The metabolic changes associated with carbon dioxide (CO(2)) pneumoperitoneum include metabolic acidosis and lowered intra-abdominal pH values. An experimental study was performed to evaluate the effect of CO(2) pneumoperitoneum on esophageal and gastric smooth muscle sensitivity in response to several agonists. METHODS: Wistar albino rats, weighing 200-250 g, were allocated into three groups. After anesthetization with ketamine hydrochloride and xylazine, abdominal esophagus, gastroesophageal junction, and gastric fundus were removed via median laparotomy in the control group. In the oxygen (O(2)) group, a 16G catheter was inserted into the abdomen above the umbilicus and insufflated with 95% O(2) and 5% CO(2) with a pressure of 10 mm Hg. In the CO(2) group, CO(2) was insufflated at the same pressure within the same time and the tissues were removed at the end of a 60 min period of pneumoperitoneum. Abdominal esophageal segment (n:6), gastroesophageal junction (n:6) and gastric fundus (n:12) were suspended under 0.5 to 2 g resting tension in Tyrode solution in organ baths. Contraction responses were obtained by carbachol and serotonin and relaxation responses were evaluated by isoproterenol in each group. All the responses were compared by nonparametric Kruskal Wallis test. RESULTS: Carbachol and serotonin induced contractile responses of abdominal segments, gastroesophageal junction, and gastric fundus showed no difference between the control, O(2), and CO(2) groups (P > 0.05). Isoproterenol relaxation responses of the three groups were also not statistically different from each other (P > 0.05). CONCLUSION: CO(2) pneumoperitoneum of 60 min has no influence on esophageal and gastric smooth muscle responses to different agonists in rats.

The effects of beta-blockers on endothelial nitric oxide synthase immunoreactivity in the rat corpus cavernosum.

OBJECTIVES: To explain the mechanism of the effects of beta-blockers on endothelial dysfunction and release of nitric oxide from the endothelium. METHODS: A total of 72 Sprague-Dawley rats were divided into 9 different groups as follows: group 1: control (n = 10), group 2: metoprolol (Beloc) 100 mg/kg/d (n = 7), group 3: carvedilol (Dilatrend) 50 mg/kg/d (n = 7), group 4: nebivolol (Vasoxen) 10 mg/kg/d (n = 6), group 5: estrogen receptor (ER) antagonist ICI 182.780 (Fluvestrant) 50 microg/g (n = 10), group 6: nebivolol+ER antagonist (n = 8), group 7: androgen receptor (AR) antagonist (flutamide) 20 mg/kg (n = 7), group 8: nebivolol+AR antagonist (n = 7), and group 9: DMSO (solvent for ER antagonist) (n = 10). All beta-blockers were applied with gastric gavage after dilution with 5 mL of serum physiological; ER and AR were both applied intraperitoneally (i.p.) for 14 days. In the isolated rat cavernous tissues, endothelial nitric oxide synthase (eNOS) and ER and AR immunoreactivity were analyzed quantitatively. One-way analysis of variance and Tukey test were used for statistical analysis. RESULTS: Although increased eNOS immunoreactivity was observed with nebivolol and nebivolol-flutamide in endothelial cells laying cavernous tissue, a lower score was observed after ICI-182.780 application, when compared with control cases. AR immunoreactivity in cavernosal endothelium was clearly higher with nebivolol. Higher H score and ER immunoreactivity were observed in the cavernous endothelium and smooth muscles in the nebivolol, carvedilol, and metoprolol groups when compared with control cases. CONCLUSIONS: We showed that eNOS activity was increased in the nebivolol and nebivolol-flutamide groups, whereas it was decreased in the ICI 182.780 group. We believe that an ER-dependent mechanism triggered by nebivolol played a role in nitric oxide formation.

Effect of whole gut irrigation solutions on gastrointestinal smooth muscle activity.

BACKGROUND/PURPOSE: It has been suggested that whole gut irrigation (WGI), which is a preparation method for large bowel surgery or colonoscopy, increases gastrointestinal motility by creating a gastrocolic reflex. An experimental study was performed to evaluate the effect of different WGI solutions on gastrointestinal smooth muscle activity. MATERIALS AND METHODS: Thirty Wistar albino rats weighing 200 to 250 g were enrolled in the study. After anesthetization with thiopental sodium (50 mg/kg), proximal ileum, terminal ileum, and colon segments were removed via median laparotomy to obtain a control group. Four different groups (n = 6) were designated as having WGI with saline solution (SS), lactated Ringer's solution (RL), polyethylene glycol (PEG), and dibasic sodium phosphate (DNP). Bowel cleaning was performed by infusing solutions at a rate of 2 mL/min via gastric tube, until the stool was cleared. After completing the bowel cleaning, 2 cm of tissues were removed and suspended in Tyrode solution in an isolated organ bath with a resting tension of 1 g, to obtain carbachol and potassium chloride (KCl) responses. RESULTS: The mean bowel cleaning times were 87.5 +/- 9.35, 81.6 +/- 9.83, 86.6 +/- 11.6, and 85.0 +/- 0.0 minutes in SS, RL, PEG, and DNP groups, respectively. The total amounts of solutions needed for cleaning were 156.67 +/- 21.6, 195.0 +/- 20.0, 197.5 +/- 32.8, and 70.0 +/- 0.0 mL, respectively. Although there was no difference in cleaning time between the groups, the amount of solution required was significantly less in the DNP group (P = .02). In the proximal ileum segments, though there was no difference in carbachol responses between groups, KCl responses were significantly increased in the RL group (P < .05). When we evaluated the terminal ileum responses, carbachol responses were significantly increased in RL and PEG groups (P = .011) and decreased in the DNP group (P = .049). The KCl responses were also significantly increased in the RL group with respect to the other groups (P < .05). Colon segments showed no difference in contractile responses with respect to different WGI solutions (P > .05, analysis of variance, post hoc Dunn's test). CONCLUSION: The different WGI solutions demonstrated no significant differences in colon contractions. The increased contractile responses in the proximal and terminal ileum segments after WGI with RL may be related to the electrolyte composition of RL. Although the lower amount of DNP solution required to achieve bowel cleaning seems to be an advantage, the decreased ileal contractions can be assessed as a disadvantage of DNP irrigations.

In vitro sensitivity of mouse esophagus to agonists in different pH medium values.

AIM: The aim of this study is to determine the in vitro sensitivity of mouse esophagus to contracting and relaxing agonists in different pH medium values. MATERIALS AND METHODS: Forty-eight Swiss albino mice (30-40 g) of both sexes were anesthetized with tiopental sodium (30 mg/kg). After exsanguinations from abdominal artery, esophagi were removed and suspended under 0.6 g of resting tension in a tissue bath containing 10 mL of Krebs solution at 37 degrees C. The experiments were performed in different pH mediums 7.4, 6.4, 4, and 2. Carbachol and acetylcholine were used as contractile agonists, and noradrenalin and isoproterenol to evaluate relaxation responses. Data concerning similar concentrations of contractile agonists obtained from different pH mediums were analyzed using Kruskal-Wallis nonparametric analysis of variance and post hoc Dunn test. Relaxation responses were compared with Student t test. A P value less than .05 was considered significant. The study was approved by Local Ethical Committee of Kirikkale University. RESULTS: Carbachol and acetylcholine caused concentration-dependent contractility in pH 7.4, 6.4, and 4, but contractile responses were inhibited in pH 2. In carbachol and acetylcholine experiments, there was a significant decrease in contractile responses to all concentrations in conjunction with a decreased in pH value. Relaxation responses in pH 2 and 4 could not be obtained because precontraction of tissues was not possible. Noradrenalin and isoproterenol produced concentration-dependent relaxations in pH 7.4 and 6.4. Although noradrenalin responses showed no significant difference according to pH, isoproterenol caused better relaxations in pH 6.4 (between 10(-8) and 10(-6) mol/L) when compared to pH 7.4 studies. CONCLUSION: The mouse esophagus has impaired contractile responses to carbachol and acetylcholine in decreased pH values. Contraction responses did not occur in pH medium of 2. In contrast, esophagus segments showed better relaxations in lower pH values with isoproterenol.