Histamine receptor in bullfrog gastric mucosa

1981 ◽  
Vol 241 (2) ◽  
pp. G93-G97
Author(s):  
S. J. Hersey
Keyword(s):  
Gastric Mucosa ◽  
Histamine Receptor ◽  
Histamine Receptors ◽  
Histamine Antagonists ◽  
Competitive Antagonism ◽  
H2 Antagonist ◽  
H2 Receptors ◽  
High Concentrations ◽  
H1 Antagonist ◽  
Very High

The histamine receptor of isolated bullfrog gastric mucosa was characterized in terms of respiration and acid secretory responses to histamine antagonists and agonists. Cimetidine, a selective H2-antagonist, showed competitive antagonism of histamine responses with a pA2 value of 6.55. In contrast, the H1-antagonist, mepyramine, showed inhibition only at very high concentrations. Based on these results, the histamine receptor would be classified as the H2 type. Measurements of agonist potency sequence revealed a marked difference between the amphibian and mammalian gastric histamine receptors. The selective H1-agonists, 2-pyridylethylamine and 2-aminoethylthiozol, were found to be more efficacious than the selective H2-agonists, dimaprit and impromidine. The lack of efficacy for dimaprit and impromidine does not appear to be due to a lack of binding to the receptor because these agents inhibit responses to histamine. For dimaprit, the inhibition was found to be competitive with an apparent pA2 value of 5.37. These results indicate that there is a molecular difference between H2-receptors in mammals versus amphibians.

Suppression of pulmonary and systemic vascular histamine H2-receptors in allergic sheep

1986 ◽  
Vol 60 (3) ◽  
pp. 791-797 ◽  
Author(s):  
T. Ahmed ◽  
M. King
Keyword(s):  
Vascular Resistance ◽  
Histamine Receptor ◽  
Base Line ◽  
Group 14 ◽  
H2 Antagonist ◽  
H2 Receptors ◽  
Pulmonary Arterial ◽  
Histamine Response ◽  
H1 Antagonist ◽  
Vasodepressor Response

We have previously demonstrated a depression of airway H2-receptor function in sheep allergic to Ascaris suum antigen. To investigate whether this is a generalized defect, we studied the H1- and H2- histamine receptor functions in the pulmonary and systemic circulations of allergic and nonallergic sheep. Pulmonary arterial pressure, and cardiac output were measured for calculation of pulmonary vascular resistance (PVR) and systemic vascular resistance (SVR) before and immediately after a rapid intrapulmonary infusion of histamine (10 micrograms/kg), with and without pretreatment with H1- (chlorpheniramine) and H2- (metiamide) antagonists. Histamine alone increased mean PVR to 435 and 401% of base line and decreased mean SVR by 51 and 54% in the nonallergic and allergic sheep, respectively (P less than 0.001). In the nonallergic sheep following pretreatment with chlorpheniramine (selective H2 stimulation) or metiamide (selective H1 stimulation), histamine decreased SVR by 18 and 36%, respectively, suggesting that approximately two-thirds of the vasodepressor response was mediated by H1-receptors and one-third by H2-receptors. Combined H1- and H2-antagonists completely blocked the histamine response. In allergic sheep the histamine-induced decrease in SVR was primarily mediated by H1-receptors, because the response was blocked by H1-antagonist, chlorpheniramine, and the H2-antagonist, metiamide, had no effect. In the pulmonary circulation selective H1-stimulation caused a similar increase in PVR in allergic (365%) and nonallergic sheep (424%), whereas selective H2-stimulation caused a significant decrease in PVR in the nonallergic group (14%) but not in the allergic group.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of histamine on microvascular permeability in the rat stomach

1983 ◽  
Vol 245 (2) ◽  
pp. G201-G207
Author(s):  
H. Nagata ◽  
P. H. Guth
Keyword(s):  
Histamine Receptors ◽  
Microvascular Permeability ◽  
In Vivo Microscopy ◽  
Rat Stomach ◽  
Serosal Surface ◽  
H2 Antagonist ◽  
H1 Antagonist ◽  
Dose Dependent ◽  
Muscularis Externa

The effect of histamine on gastric microvascular permeability to macromolecules in the rat was studied using fluorescent in vivo microscopy. Histamine was applied topically to the serosal surface for study of the muscularis externa, to the submucosa, and to the superficial mucosa, and the area of leaks of a fluorescein-albumin conjugate from microvessels was quantitated. In the muscularis externa both histamine and an H1-agonist, but not an H2-agonist, caused dose-dependent leak of conjugate from venules. An H1-antagonist, but not an H2-antagonist, decreased the histamine-induced leak. In the submucosa histamine caused dose-dependent dilatation of arterioles but not leak of conjugate. In contrast, bradykinin caused both dose-dependent dilatation of arterioles and leak of conjugate from venules. In the superficial mucosa histamine did not cause any leak. In conclusion, topical histamine 1) increased microvascular permeability to macromolecules from venules in the muscularis externa via H1-receptors, 2) did not affect microvascular permeability in the submucosa (this may be due to lack of histamine receptors on the venules as bradykinin increased venular permeability), and 3) did not affect microvascular permeability in the superficial mucosa, but there might not have been adequate histamine backdiffusion.

Effects of histamine receptor stimulation on regional myocardial blood flow

1983 ◽  
Vol 245 (3) ◽  
pp. H461-H467 ◽  
Author(s):  
C. W. Christensen ◽  
G. J. Gross ◽  
H. F. Hardman ◽  
H. L. Brooks ◽  
D. C. Warltier
Keyword(s):  
Blood Flow ◽  
Myocardial Blood Flow ◽  
Histamine Receptor ◽  
Regional Myocardial Blood Flow ◽  
Intracoronary Infusion ◽  
H2 Antagonist ◽  
Tracer Microspheres ◽  
Anesthetized Dogs ◽  
H1 Antagonist ◽  
Regional Myocardial Blood

The effect of histamine (H) and specific H1 and H2 agonists and antagonists on regional myocardial blood flow was studied in anesthetized dogs by use of tracer microspheres. Intracoronary infusion of histamine (15 and 34 micrograms/min) produced a dose-related increase in transmural myocardial blood flow (from 0.82 to 1.36 and 2.25 ml X min-1 X g-1) without alteration of heart rate or blood pressure. Infusion of the H1 agonist 2-(2-thiazolyl)ethylamine (135 and 442 micrograms/min) produced an increase in transmural perfusion (from 0.69 to 1.22 and 1.65 ml X min-1 X g-1) and a significant (P less than 0.05) increase in the ratio of flow between subendocardium and subepicardium (endo/epi from 0.97 to 1.31 and 1.54). Infusion of the H2 agonist dimaprit (195 and 390 micrograms/min) produced an increase in transmural myocardial blood flow (from 0.97 to 1.49 and 2.00 ml X min-1 X g-1) without a change in endo/epi. The H1-mediated increase in regional myocardial perfusion and endo/epi was blocked by the H1 antagonist diphenhydramine but not by the H2 antagonist cimetidine. These results suggest that stimulation of H1 coronary receptors preferentially distributes flow to the subendocardium, whereas H2 receptors mediate vasodilation in subepicardium as well as subendocardium.

Renal histamine H1 and H2 receptors: characterization and functional significance

1978 ◽  
Vol 235 (6) ◽  
pp. F570-F575
Author(s):  
R. O. Banks ◽  
J. D. Fondacaro ◽  
M. M. Schwaiger ◽  
E. D. Jacobson
Keyword(s):  
Blood Flow ◽  
Flow Distribution ◽  
Renal Vasculature ◽  
H2 Antagonist ◽  
H2 Receptors ◽  
Chloride Excretion ◽  
Intrarenal Blood Flow ◽  
Histamine H2 Antagonist ◽  
H1 Antagonist ◽  
Sustained Increase

Canine experiments were designed to determine if both histamine H1 and H2 receptors are present in the renal circulation. Renal blood flow (RBF) increased steeply over the first minute of intra-arterial histamine infusion, then increased gradually to a plateau in 3– –5 min. Infusion of either histamine + H2 antagonist or of H1 agonist produced the initial rapid increase in RBF, whereas infusion of either histamine + H1 antagonist or of H2 antagonist produced a slower but more sustained increase in RBF. Histamine significantly increased urine flow rate (V), chloride excretion, and glomerular filtration rate (GFR). Infusion of the H2 agonist also increased V and Cl excretion without affecting GFR. By contrast H1 agonist significantly reduced V and Cl excretion and tended to reduce GFR (P less than 0.1 greater than 0.05). Histamine, H1 agonist, and H2 agonist each increased inner cortical more than outer cortical blood flow. These data suggest that 1) H1 and H2 receptors are present in the renal vasculature, 2) changes in intrarenal blood flow distribution are not responsible for histamine-induced diuresis, and 3) H1 receptors are primarily postglomerular while H2 receptors exhibit both pre- and postglomerular distribution.

Characterization of H1- and H2-receptor function in pulmonary and systemic circulations of sheep

1982 ◽  
Vol 53 (1) ◽  
pp. 175-184 ◽  
Author(s):  
T. Ahmed ◽  
K. B. Mirbahar ◽  
W. Oliver ◽  
P. Eyre ◽  
A. Wanner
Keyword(s):  
Vascular Tone ◽  
Base Line ◽  
H2 Receptor ◽  
Receptor Response ◽  
H2 Antagonist ◽  
H2 Receptors ◽  
H1 Antagonist ◽  
Vasodepressor Response

We investigated the histamine H1- and H2-receptor function in the pulmonary and systemic circulations of sheep by in vivo and in vitro techniques. Combined H1 and H2 stimulation (by intravenous histamine) in vivo increased pulmonary vascular resistance (PVR) to 435% of base line and decreased systemic vascular resistance (SVR) to 49% of base line. Selective H2 stimulation (histamine after chlorpheniramine pretreatment) decreased PVR and SVR to 86 and 82% at base line, respectively, while selective H1 stimulation (histamine after metiamide pretreatment) increased PVR to 424% of base line and decreased SVR to 64% of base line. Combined H1- and H2-antagonist pretreatment completely blocked the effects of histamine on SVR, while PVR still decreased to 85% of base line, suggesting a mild “atypical” H2-receptor response in the pulmonary circulation under conditions of resting vascular tone. With increased pulmonary vascular tone (hypoxia), histamine decreased PVR to 55% (H1-antagonist pretreatment) and to 58% (combined H1- and H2-antagonist pretreatment) of posthypoxia values, respectively, demonstrating a marked atypical H2-receptor response. In vitro, both pulmonary arterial and venous strips showed a contractile dose-response to histamine, which was blocked by the H1-antagonist pyrilamine (mepyramine). In precontracted strips, both histamine and the H2-agonists (dimaprit and impromidine) elicited a relaxant response, which was neither blocked by H1-antagonist alone nor by combined H1- and H2-antagonists. We conclude that in sheep the histamine-induced pulmonary vasoconstrictor response is mediated by H1-receptors, while the pulmonary vasodepressor response is mediated by atypical H2-receptors. The systemic vasodepressor response is mediated by both H1- and typical H2-receptors.

Distribution of histamine receptors in isolated canine airways

1983 ◽  
Vol 54 (3) ◽  
pp. 693-700 ◽  
Author(s):  
S. L. Bradley ◽  
J. A. Russell
Keyword(s):  
Smooth Muscle ◽  
Histamine Receptors ◽  
Receptor Activity ◽  
Histamine H2 Receptor ◽  
H2 Receptor ◽  
H2 Antagonist ◽  
Histamine H1 Receptors ◽  
H1 Antagonist ◽  
Dose Dependent

The distribution of histamine receptors was examined in isolated trachealis smooth muscle strips and helical strips of large (5 mm) and small (1.5 mm) intrapulmonary airways. All airways contracted in response to histamine, but the sensitivity to this agent was significantly greater in intrapulmonary airways than in trachealis strips. A dose-dependent tachyphylaxis to histamine occurred when airways were exposed repeatedly to 10(-4) M histamine but not to 5 X 10(-6) M histamine. The H1-agonist, 2-methylhistamine, also caused airway contractions, although they were less forceful than those caused by histamine. Both histamine- and 2-methylhistamine-induced contractions were blocked by the H1-antagonist, pyrilamine. The H2-agonists, 4-methylhistamine and dimaprit, as well as histamine in the presence of pyrilamine failed to relax both acetylcholine- and 5-hydroxytryptamine-induced contractions. Moreover, the H2-antagonist, metiamide, had no effect on histamine-induced contractions. We conclude that histamine H1-receptors are present in both extrapulmonary and intrapulmonary airways of the dog and cause contraction when stimulated. In contrast, histamine H2-receptor activity could not be demonstrated in the airways of this species.

INFLUENCE OF SYSTEMATIC TAKING BLOCKERS OF H2-HISTAMINE RECEPTORS ON THE DEGREE OF SEMINATION OF GASTRIC MUCOSA WITH HELICOBACTER PYLORI INFECTION OF PATIENT WITH CHRONIC NON – ATROPHIC GASTRITIS

2020 ◽  
Vol 73 (11) ◽  
pp. 2503-2506
Author(s):  
Anatoly A. Avramenko
Keyword(s):  
Gastric Mucosa ◽  
Atrophic Gastritis ◽  
Histamine Receptor ◽  
Chronic Atrophic Gastritis ◽  
Main Group ◽  
Histamine Receptors ◽  
Control Group ◽  
Colloidal Bismuth Subcitrate ◽  
Urease Test ◽  
Receptor Blockers

The aim: To determine the effect of prolonged use of H2-histamine receptor blockers on the degree of contamination of the gastric mucosa with HP infection in patients with chronic non-atrophic gastritis. Materials and methods: 28 patients with chronic atrophic gastritis (the main group), who regularly took H2-histamine receptor blockers for 2 to 7 years, and 30 patients (control group), who never used them were comprehensively examined. Comprehensive examination included: step-by-step intragastric pH-metry, esophagogastroduodenoscopy, helicobacter infection test (НР) (helicobacter urease test and microscopic examination of stained smears), histological investigations of the gastric stump mucous, material for which was taken during endoscopy from 4 topographical zones: from the middle third of the gastric antrum and body of stomach on the big and small curvature. Results: All the patients in 100% of cases have confirmed the existence of chronic non-atrophic gastritis in both active and inactive stages of varying degrees of severity. Helicobacter infection was detected in 100% of cases. A comparative analysis of the data on the average degree of infection of the gastric mucosa by HP infection in the same topographic zones in the patients of the main and control groups revealed a significant (p <0.05) higher degree of seeding of the gastric mucosa in patients of the main group in all zones. Conclusions: Monotherapy for chronic non-atrophic gastritis with blockers of Н2-histamine receptors leads to an increase in the degree of gastric mucosa semination with HP infection. This fact requires mandatory parallel use of antibacterial agents – colloidal bismuth subcitrate and antibiotics, with blockers of Н2-histamine receptors.

The metachor as a characteristic of the association of electrolytes in aqueous solutions

1984 ◽  
Vol 49 (5) ◽  
pp. 1061-1078 ◽  
Author(s):  
Jiří Čeleda ◽  
Stanislav Škramovský
Keyword(s):  
Aqueous Solutions ◽  
Apparent Volume ◽  
Solutions Of Electrolytes ◽  
Molal Volumes ◽  
The Difference ◽  
High Concentrations ◽  
Experimental Values ◽  
Suitable Characteristic ◽  
Association Of Ions ◽  
Very High

Based on the earlier paper introducing a concept of the apparent parachor of a solute in the solution, we have eliminated in the present work algebraically the effect which is introduced into this quantity by the additivity of the apparent molal volumes. The difference remaining from the apparent parachor after substracting the contribution corresponding to the apparent volume ( for which the present authors suggest the name metachor) was evaluated from the experimental values of the surface tension of aqueous solutions for a set of 1,1-, 1,2- and 2,1-valent electrolytes. This difference showed to be independent of concentration up to the very high values of the order of units mol dm-3 but it was directly proportional to the number of the free charges (with a proportionality factor 5 ± 1 cm3 mol-1 identical for all studied electrolytes). The metachor can be, for this reason, a suitable characteristic for detection of the association of ions and formation of complexes in the solutions of electrolytes, up to high concentrations where other methods are failing.

scholarly journals Nitrification Process in a Nuclear Wastewater with High Load of Nitrogen, Uranium and Organic Matter under ORP Controlled

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1607
Author(s):  
Mariano Venturini ◽  
Ariana Rossen ◽  
Patricia Silva Paulo
Keyword(s):  
Ammonia Oxidation ◽  
High Load ◽  
Nuclear Fuels ◽  
Monod Model ◽  
Nernst Equation ◽  
Nitrification Process ◽  
Real Wastewater ◽  
High Concentrations ◽  
Wastewater Samples ◽  
Very High

To produce nuclear fuels, it is necessary to convert uranium′s ore into UO2-ceramic grade, using several quantities of kerosene, methanol, nitric acid, ammonia, and, in low level, tributyl phosphate (TBP). Thus, the effluent generated by nuclear industries is one of the most toxic since it contains high concentrations of dangerous compounds. This paper explores biological parameters on real nuclear wastewater by the Monod model in an ORP controlled predicting the specific ammonia oxidation. Thermodynamic parameters were established using the Nernst equation to monitor Oxiders/Reductors relationship to obtain a correlation of these parameters to controlling and monitoring; that would allow technical operators to have better control of the nitrification process. The real nuclear effluent is formed by a mixture of two different lines of discharges, one composed of a high load of nitrogen, around 11,000 mg/L (N-NH4+-N-NO3−) and 600 mg/L Uranium, a second one, proceeds from uranium purification, containing TBP and COD that have to be removed. Bioprocesses were operated on real wastewater samples over 120 days under controlled ORP, as described by Nernst equations, which proved to be a robust tool to operate nitrification for larger periods with a very high load of nitrogen, uranium, and COD.

scholarly journals Halogenated Volatile Organic Compounds in Water Samples and Inorganic Elements Levels in Ores for Characterizing a High Anthropogenic Polluted Area in the Northern Latium Region (Italy)

2021 ◽  
Vol 18 (4) ◽  
pp. 1628
Author(s):  
Mario Vincenzo Russo ◽  
Ivan Notardonato ◽  
Alberto Rosada ◽  
Giuseppe Ianiri ◽  
Pasquale Avino
Keyword(s):  
Organic Compounds ◽  
Mean Value ◽  
Greenhouse Crops ◽  
River Waters ◽  
Liquid Liquid Extraction ◽  
Volatile Organic ◽  
High Concentrations ◽  
Very High ◽  
Inorganic Fraction

This paper shows a characterization of the organic and inorganic fraction of river waters (Tiber and Marta) and ores/soil samples collected in the Northern Latium region of Italy for evaluating the anthropogenic/natural source contribution to the environmental pollution of this area. For organic compounds, organochloride volatile compounds in Tiber and Marta rivers were analyzed by two different clean-up methods (i.e., liquid–liquid extraction and static headspace) followed by gas chromatography–electron capture detector (GC-ECD) analysis. The results show very high concentrations of bromoform (up to 1.82 and 3.2 µg L−1 in Tiber and Marta rivers, respectively), due to the presence of greenhouse crops, and of chloroform and tetrachloroethene, due to the presence of handicrafts installations. For the qualitative and quantitative assessment of the inorganic fraction, it is highlighted the use of a nuclear analytical method, instrumental neutron activation analysis, which allows having more information as possible from the sample without performing any chemical-physical pretreatment. The results have evidenced high levels of mercury (mean value 88.6 µg g−1), antimony (77.7 µg g−1), strontium (12,039 µg g−1) and zinc (103 µg g−1), whereas rare earth elements show levels similar to the literature data. Particular consideration is drawn for arsenic (414 µg g−1): the levels found in this paper (ranging between 1 and 5100 µg g−1) explain the high content of such element (as arsenates) in the aquifer, a big issue in this area.

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