Stimulation by nizatidine,a histamine H_2-receptor antagonist,of duodenal HCO_3^-secretion in rats:relation to anti-cholinesterase activity

AIM To examine whether nizatidine stimulates duodenal HCO_3^- secretion in rats by inhibiting AChE activity. METHODS Under pentobarbital anesthesia,a proximal duodenal loop was perfused with saline,and the HCO_3 secretion was measured at pH 7.0 using a pH-stat method and by adding 10mM HCI.Nizatidine,neostigmine,carbachol or famotidine was administered i.v.as a single injection. RESULTS Intravenous administration of nizatidine(3-30 mg/kg)dose-dependently increased duodenal HCO_3^- secretion,and the effect at 10mg/kg was equivalent to that obtained by carbachol at 0.01 mg/kg.This nizatidine action was observed at the same dose range that inhibited acid secretion and enhanced gastric motility,mimicked by i.v.injection of neostigmine(0.03 mg/kg),and significantly attenuated by bilateral vagotomy and prior s.c. administration of atropine but not by indomethacin,a cyclooxygenase inhibitor,or N^G-nitro-L-arginine methyl ester,a NO synthase inhibitor.The HCO_3^- secretory response to acetylcholine(0.001 mg/kg)was significantly potentiated by the concurrent administration of nizatidine(3mg/kg,i.v.).The IC_(50)of nizatidine for AChE of rat erythrocytes was 1.4×10^(-6)M,about 12 times higher than that of neostigmine.Neither famotidine(>10^(-3)M, 30mg/kg,i.v.)nor cisapride(> 10^(-3)M, 3mg/kg,i.v.)had any influence on AChE activity or duodenal HCO_3^- secretion.Duodenal damage induced by acid perfusion(100 mM HCI for 4 h)in the presence of indomethacin was significantly prevented by nizatidine and neostigmine,at the doses that increased the HCO_3^- secretion. CONCLUSION Nizatidine stimulates duodenal HCO_3^- secretion,in both vagal-dependent and atropine-sensitive manners,and the action is associated with the anti-AChE activity of this agent.

Ameliorating Effects of Thyroxine and Atropine in Phosphamidon Intoxicated Chick Embryos

The effects of thyroxine and atropine in ameliorating phosphamidon intoxication in chick embryos was studied. Treatment of phosphamidon significantly enhanced the moriality and abnormalityrates, decreased the average body weights, and cholinesterase activity in chick embryos. When thyroxine was administered to the phosphamidon intoxicated embryos, the above parameters changedsignificantly, indicating an ameliorating effect of thyroxine against phosphamidon intoxication in chick embryos. The combined thyroxine and atropine therapy did not further improve the ameliorating effect. Since in many respects chick embryo development parallels that of mammalian embryos,a short-term use of thyroxine as a protective agent against organophosphate toxicity might be useful

Assessment of Pesticide Use against Tephritidae Fruit Fly and Other Pest among Small-scale Solanaceous Vegetable Farmers in Bugorhe-Kabare the Democratic Republic of Congo

Ninety-six farmers interviewed in Kabare,east of the DR Congo during 2021.Farmers majority were males(79.17%),ranging 30 to 60 years,used different pesticides in vegetable farms and the main solanaceous crops cultivated is tomato.The use of insecticide and fungicide were high,with many different formulations of the different class types recorded in use,(20%)endocrine disruptors,(40%)cholinesterase inhibitors,(35%)carcinogen and potential carcinogens suspected to be.A lot of out of those pesticides are unregistered for general use.Farmers applied pesticide once a week and they didn’t have specific instructions.The skin effects,headaches and dizziness are dominant.They do not have a good system of pesticide packaging management.For reducing pesticide application,we propose options of agro ecology.We suggest that the Congolese government must create a quarantine,control and surveillance service for phytosanitary products,fruits and vegetables within the DRC country and at these borders.Also,it needs urgent action from the federal and regional governments to formulate policy,design legislation,and enforcing for its implementation concerning the supply,transportation,storage,appropriateness,and application of harmful pesticides.

Clinical correlates of hypotension in patients with acute organophosphorus poisoning

BACKGROUND:The aim of the present study is to describe the clinical correlates of hypotension and its associated outcomes in patients with acute organophosphorus poisoning(AOPP).METHODS:In this retrospective cohort study,we analyzed data pertaining to 871 patients with AOPP who were treated at two hospitals.Data from hypotensive and non-hypotensive patients were compared to identify clinical correlates of hypotension.We also evaluated the association between clinical parameters(including hypotension)and in-hospital mortality.RESULTS:The incidence of hypotension in AOPP patients was 16.4%.Hypotensive patients showed signifi cantly higher in-hospital mortality(1.1%vs.39.9%,P<0.001).Advanced age(odds ratio[OR]1.25,95%confi dence interval[CI]1.08–1.44),history of diabetes(OR 2.65,95%CI 1.14–5.96),and increased white blood cell count(OR 1.06,95%CI 1.03–1.09),plasma cholinesterase(OR 0.91,95%CI 0.84–0.94),plasma albumin(OR 0.88,95%CI 0.85–0.92),serum amylase(OR 1.01,95%CI 1.01–1.02),and blood pH(OR 0.64,95%CI 0.54–0.75)were signifi cantly associated with hypotension.After adjusting for potential confounders,hypotension was associated with increased in-hospital mortality(hazard ratio 8.77–37.06,depending on the controlled variables).CONCLUSIONS:Hypotension is a common complication of AOPP and is associated with increased in-hospital mortality.Advanced age,history of diabetes,and changes in laboratory parameters were associated with hypotension in AOPP patients.

Bis(7)-Tacrine, a Promising Anti-Alzheimer's Agent,Attenuates Glutamate-Induced Cell Injury in Primary Cultured Cerebrocortical Neurons of Rats

The effects of bis(7) tacrine, a novel dimeric acetylcholinesterase (AChE) inhibitor, on glutamate induced cell injury were investigated in primary cerebral cortical neurons of rats. Exposure of cultured neurons (12 days after plating) to 0.5 mmol/L glutamate for 30 min resulted in significant cell damage. Pretreatment with bis(7) tacrine (0.03 1.0 μmol/L) reduced the glutamate induced neurotoxicity in a concentration dependent manner and the maximal response was seen at 1 μmol/L with approximately 30% protection. A receptor binding assay showed that bis(7) tacrine can completely displace MK 801 binding to rat cortical membrane with an IC 50 of 0.57 μmol/L. These findings suggest that bis(7) tacrine can directly interact with N methyl D aspartate receptor channel complex, which may contribute to the inhibitor's protective effects against glutamate induced excitotoxicity. Thus, it is possible that anti glutamate/anti AChE synergism is responsible for potentially better Alzheimer's therapy of bis(7) tacrine relative to tacrine.

Effect of cholinesterase inhibitor galanthamine on circulating tumor necrosis factor alpha in rats with lipopolysaccharideinduced peritonitis

Background The nervous system, through the vagus nerve and its neurotransmitter acetylcholine, can down-regulate the systemic inflammation in vivo, and recently, a role of brain cholinergic mechanisms in activating this cholinergic anti-inflammatory pathway has been indicated. Galanthamine is a cholinesterase inhibitor and one of the centrally acting cholinergic agents available in clinic. This study aimed to evaluate the effect of galanthamine on circulating tumor necrosis factor alpha （TNF-a） in rats with lipopolysaccharide-induced peritonitis and the possible role of the vagus nerve in the action of galanthamine. Methods Rat models of lipopolysaccharide-induced peritonitis and bilateral cervical vagotomy were produced. In the experiment 1, the rats were randomly divided into control group, peritonitis group, and peritonitis groups treated with three dosages of galanthamine. In the experiment 2, the rats were randomly divided into sham group, sham plus peritonitis group, sham plus peritonitis group treated with galanthamine, vagotomy plus peritonitis group, and vagotomy plus peritonitis group treated with galanthamine. The levels of plasma TNF-α were determined in every group. Results The level of circulating TNF-α was significantly increased in rats after intraperitoneal injection of endotoxin. Galanthamine treatment decreased the level of circulating TNF-α in rats with lipopolysaccharide-induced peritonitis, and there was significant difference compared with rats with lipopolysaccharide-induced peritonitis without treatment. The 3 mg/kg dosage of galanthamine had the most significant inhibition on circulating TNF-α level at all the three tested doses. Galanthamine obviously decreased the TNF-a level in rats with lipopolysaccharide-induced peritonitis with sham operation, but could not decrease the TNF-α level in rats with lipopolysaccharide-induced peritonitis with vagotomy. Conclusion Cholinesterase inhibitor galanthamine has an inhibitory effect on TNF-α release in rats with Iipopolysaccharide-induced peritonitis, and the vagus nerve plays a role in the process of the action of galanthamine.

Searching for new drugs to treat Alzheimer’s disease dementia through multiple pathways

Dementia is a group of diseases,including Alzheimer's disease(AD),vascular dementia,Lewy body dementia,frontotemporal dementia,Parkinson's disease dementia,metabolic dementia and toxic dementia.The treatment of dementia mainly includes symptomatic treatment by controlling the primary disease and accompanying symptoms,nutritional support therapy for repairing nerve cells,psychological auxiliary treatment,and treatment that improves cognitive function through drugs.Among them,drug therapy to improve cognitive function is important.This review focuses on introducing and commenting on some recent progress in exploring drugs to improve cognitive function,especially the new progress in drug treatment for AD.We mainly discuss the opportunities and challenges in finding and developing new therapeutic drugs from the aspects of acetylcholinesterase,N-methyl-D-aspartate glutamate receptor,amyloid protein,tau protein and chronic immune inflammation.