Comparison of the effects of aging in vivo and of oxygen free radicals in vitro on high-affinity choline uptake and hemicholinium-3 binding in the rat brain

1993 ◽  
Vol 17 (3) ◽  
pp. 179-188 ◽  
Author(s):  
Z. Krištofiková ◽  
O. Benešová ◽  
H. Tejkalová
Keyword(s):  
Free Radicals ◽  
Rat Brain ◽  
Oxygen Free Radicals ◽  
Choline Uptake ◽  
High Affinity ◽  
Effects Of Aging

Effect of Hyperbaric Oxygen Treatment on Nitric Oxide and Oxygen Free Radicals in Rat Brain

2000 ◽  
Vol 83 (4) ◽  
pp. 2022-2029 ◽  
Author(s):  
Ikram M. Elayan ◽  
Milton J. Axley ◽  
Paruchuri V. Prasad ◽  
Stephen T. Ahlers ◽  
Charles R. Auker
Keyword(s):  
Nitric Oxide ◽  
Free Radicals ◽  
Rat Brain ◽  
Hyperbaric Oxygen ◽  
High Pressures ◽  
Oxygen Free Radicals ◽  
In Vivo Microdialysis ◽  
Sprague Dawley ◽  
Fourfold Increase

Oxygen (O2) at high pressures acts as a neurotoxic agent leading to convulsions. The mechanism of this neurotoxicity is not known; however, oxygen free radicals and nitric oxide (NO) have been suggested as contributors. This study was designed to follow the formation of oxygen free radicals and NO in the rat brain under hyperbaric oxygen (HBO) conditions using in vivo microdialysis. Male Sprague-Dawley rats were exposed to 100% O2 at a pressure of 3 atm absolute for 2 h. The formation of 2,3-dihydroxybenzoic acid (2,3-DHBA) as a result of perfusing sodium salicylate was followed as an indicator for the formation of hydroxyl radicals. 2,3-DHBA levels in hippocampal and striatal dialysates of animals exposed to HBO conditions were not significantly different from controls. However, rats treated under the same conditions showed a six- and fourfold increase in nitrite/nitrate, break down products of NO decomposition, in hippocampal and striatal dialysates, respectively. This increase was completely blocked by the nitric oxide synthase (NOS) inhibitor l-nitroarginine methyl ester (l-NAME). Using neuronal NOS, we determined the NOS O2 K m to be 158 ± 28 (SD) mmHg, a value which suggests that production of NO by NOS would increase approximately four- to fivefold under hyperbaric O2 conditions, closely matching the measured increase in vivo. The increase in NO levels may be partially responsible for some of the detrimental effects of HBO conditions.

scholarly journals Syntheses and In-vitro Evaluation of Tetrahydroaminoacridine (THA) Based Analogues as High Affinity Choline Transporter (HAChT) Imaging Probe

2016 ◽  
Vol 17 (2) ◽  
pp. 97-102
Author(s):  
Mohammad Anwar Ul Azim ◽  
Takashi Kozaka ◽  
Izumi Uno ◽  
Daisuke Miwa ◽  
Yoji Kitamura ◽  
...  
Keyword(s):  
Binding Assay ◽  
Research Work ◽  
Cholinergic Neurons ◽  
Choline Uptake ◽  
Choline Transporter ◽  
High Affinity ◽  
20 Nm ◽  
High Affinity Choline Transporter

Introduction: In cholinergic neurons, high affinity choline uptake (HACU) by the high affinity choline transporter (HAChT) is a rate-limiting and regulatory step for the synthesis of Acetylcholine (Ach).Thus, HAChT appear to be a relatively specific presynaptic marker for cholinergic neurons in Alzheimer’s disease.Objectives: The principle objective of the study is to check the affinity of tetrahydroaminoacridine (THA) derivatives for HAChT. Another objective of the research work is to clarify whether the hemicholinium-3 (ChT inhibitor) and HACU enhancer molecules share the same binding sites or not.Materials and Methods: The inhibition activities of tacrine, the 2,3-dimethylfuran derivative of tacrine (DMTA) and their corresponding 2-oxo-1-pyrrolidineacetyl derivatives, namely PTAA and MKC-231 were measured by displacement of a typical HAChT antagonist [3H]HC-3 in rat cerebral membrane. The percentage of inhibition against the binding of [3H]HC-3 to HAChT were calculated using GraphPad Prism v4 software.Results: Hemicholinium-3 showed affinity for HAChT (IC50 = 20 nM) in the in vitro binding assay. A very insignificant inhibition activity (IC50 = 1000 nM) of Tacrine was revealed. The newly synthesized tacrine derivatives, DMTA and PTAA did not show any affinity for HAChT. Although MKC-231 was reported to enhance cholinergic activity at synaptic terminals, it did not show any affinity for the HAChT in [3H]HC-3 binding assay.Conclusion: In vitro [3H]HC-3 binding assay revealed no affinity of MKC-231, tacrine and its corresponding2-oxo-1-pyrrolidineacetate derivative towards HAChT. So, it is worthy to develop radiolabeled HC-3 derivatives with high affinity for HAChT, which can diffuse the BBB, to enable the in vivo investigation of HACU system.Bangladesh J. Nuclear Med. 17(2): 97-102, July 2014

scholarly journals Phosphorylation of human topoisomerase I by protein kinase C in vitro and in phorbol 12-myristate 13-acetate-activated HL-60 promyelocytic leukaemia cells

1993 ◽  
Vol 291 (1) ◽  
pp. 303-307 ◽  
Author(s):  
E Cardellini ◽  
E Durban
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Rat Brain ◽  
Topoisomerase I ◽  
Promyelocytic Leukaemia ◽  
High Affinity ◽  
Kinase C ◽  
Phosphopeptide Mapping

Topoisomerase I was phosphorylated in vitro by protein kinase C (PKC) purified from rat brain with high affinity (Km about 0.1 microM). Tryptic phosphopeptide mapping indicated that two major topoisomerase I peptides phosphorylated in vivo were comigrating with minor peptides phosphorylated by PKC in vitro. Topoisomerase I phosphorylation was stimulated 3-fold in HL-60 cells exposed to the tumour promoter phorbol 12-myristate 13-acetate. The results suggest that topoisomerase I phosphorylation in HL-60 cells is indirectly controlled by PKC.

High affinity dopamine D2 receptor radioligands. 3. [123I] and [125I]epidepride: In vivo studies in rhesus monkey brain and comparison with in vitro pharmacokinetics in rat brain

Life Sciences ◽  
1993 ◽  
Vol 53 (3) ◽  
pp. 241-250 ◽  
Author(s):  
Robert M. Kessler ◽  
John R. Votaw ◽  
Dennis E. Schmidt ◽  
M. Sib Ansari ◽  
Karen P. Holdeman ◽  
...  
Keyword(s):  
Rhesus Monkey ◽  
Rat Brain ◽  
Dopamine D2 Receptor ◽  
D2 Receptor ◽  
In Vivo Studies ◽  
Monkey Brain ◽  
High Affinity ◽  
Rhesus Monkey Brain

Effects of Heparin Oligosaccharides with High Affinity for Antithrombin III in Experimental Venous Thrombosis

1982 ◽  
Vol 47 (03) ◽  
pp. 244-248 ◽  
Author(s):  
D P Thomas ◽  
Rosemary E Merton ◽  
T W Barrowcliffe ◽  
L Thunberg ◽  
U Lindahl
Keyword(s):  
Antithrombin Iii ◽  
Specific Activity ◽  
High Specific Activity ◽  
Factor Xa ◽  
Blood Levels ◽  
Thrombin Time ◽  
High Affinity ◽  
Very High

SummaryThe in vitro and in vivo characteristics of two oligosaccharide heparin fragments have been compared to those of unfractionated mucosal heparin. A decasaccharide fragment had essentially no activity by APTT or calcium thrombin time assays in vitro, but possessed very high specific activity by anti-Factor Xa assays. When injected into rabbits at doses of up to 80 ¼g/kg, this fragment was relatively ineffective in impairing stasis thrombosis despite producing high blood levels by anti-Xa assays. A 16-18 monosaccharide fragment had even higher specific activity (almost 2000 iu/mg) by chromogenic substrate anti-Xa assay, with minimal activity by APTT. When injected in vivo, this fragment gave low blood levels by APTT, very high anti-Xa levels, and was more effective in preventing thrombosis than the decasaccharide fragment. However, in comparison with unfractionated heparin, the 16-18 monosaccharide fragment was only partially effective in preventing thrombosis, despite producing much higher blood levels by anti-Xa assays.It is concluded that the high-affinity binding of a heparin fragment to antithrombin III does not by itself impair venous thrombogenesis, and that the anti-Factor Xa activity of heparin is only a partial expression of its therapeutic potential.

Novel concatameric heparin-binding peptides reverse heparin and low-molecular-weight heparin anticoagulant activities in patient plasma in vitro and in rats in vivo

Blood ◽  
2004 ◽  
Vol 103 (4) ◽  
pp. 1356-1363 ◽  
Author(s):  
Barbara P. Schick ◽  
David Maslow ◽  
Adrianna Moshinski ◽  
James D. San Antonio
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight Heparin ◽  
Tandem Repeats ◽  
Factor Xa ◽  
Low Molecular Weight ◽  
Heparin Binding ◽  
High Affinity ◽  
Binding Peptides

Abstract Patients given unfractionated heparin (UFH) or low-molecular-weight heparin (LMWH) for prophylaxis or treatment of thrombosis sometimes suffer serious bleeding. We showed previously that peptides containing 3 or more tandem repeats of heparin-binding consensus sequences have high affinity for LMWH and neutralize LMWH (enoxaparin) in vivo in rats and in vitro in citrate. We have now modified the (ARKKAAKA)n tandem repeat peptides by cyclization or by inclusion of hydrophobic tails or cysteines to promote multimerization. These peptides exhibit high-affinity binding to LMWH (dissociation constant [Kd], ≈ 50 nM), similar potencies in neutralizing anti–Factor Xa activity of UFH and enoxaparin added to normal plasma in vitro, and efficacy equivalent to or greater than protamine. Peptide (ARKKAAKA)3VLVLVLVL was most effective in all plasmas from enoxaparin-treated patients, and was 4- to 20-fold more effective than protamine. Several other peptide structures were effective in some patients' plasmas. All high-affinity peptides reversed inhibition of thrombin-induced clot formation by UFH. These peptides (1 mg/300 g rat) neutralized 1 U/mL anti–Factor Xa activity of enoxaparin in rats within 1 to 2 minutes. Direct blood pressure and heart rate measurements showed little or no hemodynamic effect. These heparin-binding peptides, singly or in combination, are potential candidates for clinical reversal of UFH and LMWH in humans.

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