Histamine at low concentrations aggravates rat liver BRL-3A cell injury induced by hypoxia/reoxygenation through histamine H2 receptor in vitro

2013 ◽  
Vol 27 (1) ◽  
pp. 378-386 ◽  
Author(s):  
Tiansheng Wu ◽  
Xiaoliang Gan ◽  
Shaoli Zhou ◽  
Mian Ge ◽  
Zheng Zhang ◽  
...  
Keyword(s):  
Rat Liver ◽  
Cell Injury ◽  
Histamine H2 Receptor ◽  
H2 Receptor ◽  
Low Concentrations ◽  
Hypoxia Reoxygenation

scholarly journals HIGH-YIELD PREPARATION OF ISOLATED RAT LIVER PARENCHYMAL CELLS

1969 ◽  
Vol 43 (3) ◽  
pp. 506-520 ◽  
Author(s):  
M. N. Berry ◽  
D. S. Friend
Keyword(s):  
Gap Junctions ◽  
Rat Liver ◽  
Structural Integrity ◽  
Cell Injury ◽  
High Yield ◽  
Isolated Cells ◽  
Nylon Mesh ◽  
Parenchymal Cells

A new technique employing continuous recirculating perfusion of the rat liver in situ, shaking of the liver in buffer in vitro, and filtration of the tissue through nylon mesh, results in the conversion of about 50% of the liver into intact, isolated parenchymal cells. The perfusion media consist of: (a) calcium-free Hanks' solution containing 0.05% collagenase and 0.10% hyaluronidase, and (b) magnesium and calcium-free Hanks' solution containing 2 mM ethylenediaminetetraacetate. Biochemical and morphologic studies indicate that the isolated cells are viable. They respire in a medium containing calcium ions, synthesize glucose from lactate, are impermeable to inulin, do not stain with trypan blue, and retain their structural integrity. Electron microscopy of biopsies taken during and after perfusion reveals that desmosomes are quickly cleaved. Hemidesmosome-containing areas of the cell membrane invaginate and appear to pinch off and migrate centrally. Tight and gap junctions, however, persist on the intact, isolated cells, retaining small segments of cytoplasm from formerly apposing parenchymal cells. Cells which do not retain tight and gap junctions display swelling of Golgi vacuoles and vacuoles in the peripheral cytoplasm. Cytoplasmic vacuolization in a small percentage of cells and potassium loss are the only indications of cell injury detected. By other parameters measured, the isolated cells are comparable to normal hepatic parenchymal cells in situ in appearance and function.

Histamine H2-receptor of human and rabbit parietal cells

1987 ◽  
Vol 253 (4) ◽  
pp. G497-G501 ◽  
Author(s):  
R. Leth ◽  
B. Elander ◽  
U. Haglund ◽  
L. Olbe ◽  
E. Fellenius
Keyword(s):  
Dose Response ◽  
In Vivo Model ◽  
Response Curves ◽  
Gastric Glands ◽  
Histamine H2 Receptor ◽  
Receptor Affinity ◽  
H2 Receptor ◽  
Dose Response Curves

The histamine H2-receptor on the human parietal cell has been characterized by using dose-response curves and the negative logarithm of the molar concentration of an antagonist (pA2) analyses of cimetidine antagonism of betazole, histamine, and impromidine stimulation in isolated human and rabbit gastric glands. To evaluate the in vitro results, betazole-stimulated gastric acid secretion with and without cimetidine was also studied in healthy subjects. In the in vivo model, individual dose-response curves were shifted to the right with increasing cimetidine concentrations, but this was counteracted by increasing betazole doses, indicating competitive, reversible antagonism. The pA2 values ranged from 6.1 to 6.3. In isolated human gastric glands, impromidine was shown to be eight times more potent than histamine, indicating higher receptor affinity, but the maximally stimulated aminopyrine accumulation was the same as for histamine, and the pA2 values for cimetidine antagonism did not differ significantly, i.e., 5.7 (histamine) and 6.1 (impromidine). In isolated rabbit gastric glands, cimetidine inhibited the histamine- and impromidine-stimulated response with pA2 values of 6.0 and 7.3, respectively. Impromidine was shown to be approximately 100 times more potent than in human gastric glands, whereas histamine had the same potency. This confirms the role of the histamine H2-receptor and suggests a difference between the species concerning receptor affinity.

Effect of a histamine H2-receptor antagonist on immunologically induced mediator release in vitro

1974 ◽  
Vol 4 (5) ◽  
pp. 297-303 ◽  
Author(s):  
L. W. Chakrin ◽  
R. D. Krell ◽  
J. Mengel ◽  
D. Young ◽  
C. Zaher ◽  
...  
Keyword(s):  
Receptor Antagonist ◽  
Mediator Release ◽  
H2 Receptor Antagonist ◽  
Histamine H2 Receptor ◽  
H2 Receptor ◽  
Release In Vitro ◽  
Histamine H2 Receptor Antagonist

Alteration of activation energy of reaction in the catalase of human erythrocyte by cimetidine, an in vitro thermokinetics study

2020 ◽  
Vol 09 ◽  
Author(s):  
Dariush Minai-Tehrani
Keyword(s):  
Activation Energy ◽  
Human Erythrocyte ◽  
Cell Injury ◽  
Gastrointestinal Diseases ◽  
Maximum Activity ◽  
The Body ◽  
Effect Of Temperature ◽  
Histamine H2 Receptor ◽  
In Cells

Background: Hydrogen peroxide is normally formed during the metabolic pathway of the body. It is a toxic compound for vital cells, which can oxidize many macromolecules and cause damage in cells. Catalase can degrade H2O2 in cells and prevent cell injury. Cimetidine is a histamine H2 receptor blocker which decreases the release of stomach acid and is used for gastrointestinal diseases. Cimetidine inhibited catalase by mixed inhibition. Objective: In this study, effect of temperature on the binding of cimetidine to human erythrocyte catalase was investigated and kinetic factors of the binding were determined. Results: Dixon plot confirmed the mixed type of inhibition and determined the Ki of the drug. Maximum activity of the enzyme was observed at 30oC. Arrhenius plot demonstrated that the activation energy of the enzyme reaction in the absence and presence of cimetidine was about 4.7 and 8.13 kJ/mol, respectively. Temperature coefficient (Q30-40) was determined as about 1.11 and 1.09 in the absence and presence of cimetidine. Conclusion: Cimetidine was able to increase the activation energy of the reaction of catalase, which confirmed the inhibition of the enzyme based on the kinetic results.

scholarly journals Transcription of rat liver deoxyribonucleic acid in vitro at low ionic strength

1978 ◽  
Vol 175 (1) ◽  
pp. 1-13 ◽  
Author(s):  
E Pays
Keyword(s):  
Rna Polymerase ◽  
Rat Liver ◽  
Chain Elongation ◽  
Rna Sequences ◽  
Double Stranded Dna ◽  
Low Concentrations ◽  
Dna 2 ◽  
Low Ionic Strength ◽  
Dna Ends

1. When RNA polymerase is in excess over DNA, the single-stranded breaks of DNA can be recognized as initiation sites for the ezyme. On the other hand stabel initiation complexes (resistant to inhibition by heparin) are the most abundant under these conditions. The formation of these complexes needs double-stranded DNA. It seems that RNA sequences rich in cytidine are preferentially synthesized; since rat liver DNA is A + T-rich, the transcription thus appears not to be random with respect to the base composition of DNA. 2. When the template is in excess over the polymerase, the single-stranded gaps of DNA are preferentially transcribed by rat liver RNA polymerase B and native DNA regions by Escherichia coli RNA polymerase. 3. With a large excess of DNA over the polymerase, the enzyme activity is markedly inhibited. This inhibition is proportional to the concentration of double-stranded DNA ends, but it also depends on the presence of a contaminant of DNA, removed when DNA is banded in a CsCl gradient. This contaminant could be polyphosphates. Low concentrations of spermine completely reverse this inhibition, by enhancing the rate of RNA chain elongation. 4. Double-stranded RNA is synthesized in great abundance when RNA polymerase is in excess over native DNA. Besides a majority of symmetrical sequences, stable ‘hairpins’ can be found. Whereas the synthesis of symmetrical sequences is more prevalent in polymerase excess, it seems that the proportion of stable ‘hairpins’ in RNA is independent of the polymerase/DNA ratio.

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