Relative agonist potency as a means of differentiating α-adrenoceptors and α-adrenergic mechanisms

1985 ◽  
Vol 68 (s10) ◽  
pp. 9s-15s ◽  
Author(s):  
Robert R. Ruffolo
Keyword(s):  
Guinea Pig ◽  
Species Differences ◽  
Dissociation Constants ◽  
Rat Aorta ◽  
Adrenergic Mechanisms ◽  
Qualitative And Quantitative ◽  
Adrenoceptor Agonists ◽  
Relative Potencies

1. Relative potencies (ED50), affinities (assessed as dissociation constants) and efficacies (i.e. ability to activate the receptor) of agonists are useful in subclassifying and differentiating α-adrenoceptors. 2. The postsynaptic α-adrenoceptor of rat aorta is of the α1-subtype, but may differ from the α1-adrenoceptor of rabbit and guinea pig aortae, based on comparison of relative potencies of selected agonists. 3. By evaluating the relative potency of agonists, qualitative and quantitative species differences between α1-adrenoceptors in rat and guinea pig are observed in a variety of test systems in vivo and in vitro. 4. By comparing the relative potencies of aromatic hydroxyl-substituted phenethylamines and imidazolines at α1-adrenoceptors in guinea pig aorta, differences in the ability of these two classes of α-adrenoceptor agonists to bind to, and subsequently activate, α1-adrenoceptors have been observed. 5. Evaluating the relative potencies of agonists, when used in conjunction with other techniques, provides a valuable method for classifying α-adrenoceptors and for studying α-adrenergic mechanisms.

Species differences in the reactivation of organophosphate-inhibited plasma esterases by diacetymonoxime

1976 ◽  
Vol 54 (2) ◽  
pp. 86-92 ◽  
Author(s):  
D. J. Ecobichon
Keyword(s):  
Guinea Pig ◽  
Species Differences ◽  
Marked Effect ◽  
Lethal Dose ◽  
Rat Plasma ◽  
In Vivo Studies ◽  
Rapid Rate ◽  
Plasma Enzymes

A study was conducted to assess whether the protection afforded to organophosphate-poisoned animals by diacetylmonoxime (DAM) was correlated with the reactivation of non-essential aliesterases (AliE). In vitro, the DAM-catalyzed reactivation of plasma AliE and cholinesterases (ΨChE) of rat, rabbit and guinea pig inhibited by 10−5 M diisopropylphosphorofluoridate (DFP) and O,O-dimethyl-2,2-dichlorovinyl phosphate (DDVP) was investigated. Marked reactivation of the rat plasma enzymes was achieved with 10 mM DAM. Higher concentrations (30 mM) were necessary for the slow reactivation of rabbit and guinea pig plasma AliE. Reactivation of the ΨChE of these species was comparatively slow. Reactivation of DDVP-inhibited esterases proceeded in all species at a more rapid rate than those inhibited by DFP. The dependence of ΨChE reactivation upon concomitant more rapid reactivation of AliE by DAM was demonstrated using Sephadex fractionated AliE and ΨChE but only a marked effect was observed with the rat, suggesting that the plasma AliE of this species is functionally different.The in vitro observations were confirmed by in vivo studies in rats and rabbits. DAM (50 or 150 mg/kg), administered to atropinized rats 15 min before a lethal dose of DFP, protected the animals. Few severe toxic signs were observed and reactivation of both plasma AliE and ΨChE occurred. In contrast, DAM protected the rabbit against a lethal dose of DFP but only reactivation of the erythrocyte acetylcholinesterase was observed.

Tachyphylaxis to β-adrenoceptor agonists in guinea pig airway smooth muscle in vivo and in vitro

1977 ◽  
Vol 42 (3) ◽  
pp. 195-205 ◽  
Author(s):  
James S. Douglas ◽  
Alan J. Lewis ◽  
Pamela Ridgway ◽  
Charles Brink ◽  
Arend Bouhuys
Keyword(s):  
Smooth Muscle ◽  
Guinea Pig ◽  
Airway Smooth Muscle ◽  
Adrenoceptor Agonists

Inhibition of Human and Animal Platelet Adhesiveness to Glass Bead Columns by Adenosine, Dipyridamole, Chlorpromazine and Acetylsalicylic Acid

1976 ◽  
Vol 36 (02) ◽  
pp. 401-410 ◽  
Author(s):  
Buichi Fujttani ◽  
Toshimichi Tsuboi ◽  
Kazuko Takeno ◽  
Kouichi Yoshida ◽  
Masanao Shimizu
Keyword(s):  
Guinea Pig ◽  
Acetylsalicylic Acid ◽  
Guinea Pigs ◽  
Glass Bead ◽  
Animal Species ◽  
Inhibitory Effect ◽  
Rabbit Platelet ◽  
Platelet Adhesiveness

SummaryThe differences among human, rabbit and guinea-pig platelet adhesiveness as for inhibitions by adenosine, dipyridamole, chlorpromazine and acetylsalicylic acid are described, and the influence of measurement conditions on platelet adhesiveness is also reported. Platelet adhesiveness of human and animal species decreased with an increase of heparin concentrations and an increase of flow rate of blood passing through a glass bead column. Human and rabbit platelet adhesiveness was inhibited in vitro by adenosine, dipyridamole and chlorpromazine, but not by acetylsalicylic acid. On the other hand, guinea-pig platelet adhesiveness was inhibited by the four drugs including acetylsalicylic acid. In in vivo study, adenosine, dipyridamole and chlorpromazine inhibited platelet adhesiveness in rabbits and guinea-pigs. Acetylsalicylic acid showed the inhibitory effect in guinea-pigs, but not in rabbits.

Anticoagulant Properties of Three Mucopolysaccharides Used in Rheumatology

1983 ◽  
Vol 50 (03) ◽  
pp. 652-655 ◽  
Author(s):  
F Bauer ◽  
P Schulz ◽  
G Reber ◽  
C A Bouvier
Keyword(s):  
Factor Xa ◽  
Degenerative Joint Disease ◽  
Joint Disease ◽  
Thrombin Time ◽  
Coagulation Tests ◽  
Amplification System ◽  
Relative Potencies ◽  
In Vivo Administration

SummaryThree mucopolysaccharides (MPS) used in the treatment of degenerative joint disease were compared to heparin to establish their relative potencies on 3 coagulation tests, the aPTT, the antifactor X a activity and the dilute thrombin time. One of the compounds, Arteparon®, was one fourth as potent as heparin on the aPTT, but had little or no influence on the 2 other tests. Further in vitro studies suggested that Arteparon® acted at a higher level than factor Xa generation in the intrinsic amplification system and that its effect was independent of antithrombin III. In vivo administration of Arteparon® confirmed its anticoagulant properties, which raises the question of the clinical use of this MPS.

Effects of summer mailing on in vivo and in vitro relative potencies of standardized timothy grass extract

2010 ◽  
Vol 104 (2) ◽  
pp. 147-151 ◽  
Author(s):  
Meredith Moore ◽  
Mark Tucker ◽  
Tom Grier ◽  
James Quinn
Keyword(s):  
Timothy Grass ◽  
Relative Potencies

scholarly journals Inside Front Cover: Species Differences in in vitro and Estimated in vivo Kinetics for Intestinal Microbiota Mediated Metabolism of Acetyl‐deoxynivalenols

2021 ◽  
Vol 65 (9) ◽  
pp. 2170020
Author(s):  
Jing Jin ◽  
Albertus Spenkelink ◽  
Karsten Beekmann ◽  
Marta Baccaro ◽  
Fuguo Xing ◽  
...  
Keyword(s):  
Intestinal Microbiota ◽  
Species Differences ◽  
Front Cover ◽  
In Vivo Kinetics

The control of trophoblastic growth in the guinea pig

Development ◽  
1980 ◽  
Vol 60 (1) ◽  
pp. 405-418
Author(s):  
E. B. Ilgren
Keyword(s):  
Guinea Pig ◽  
Inner Cell Mass ◽  
Cell Mass ◽  
The Other ◽  
In Vivo Analysis

The growth of mouse trophectoderm depends upon the presence of the inner cell mass. Whether this applies to other species of mammals is not known. To investigate this problem, the guinea pig was selected for two reasons. Firstly, the growth of guinea-pig trophoblast resembles that of man. Secondly, earlier studies suggest that the proliferation of guinea-pig trophectoderm may not be under ICM control. Therefore, in the present study, the guinea-pig blastocyst was cut microsurgically to yield two tissue fragments. These contained roughly equal numbers of trophectodermal cells, one fragment being composed only of trophectoderm and the other containing ICM tissue as well. Subsequently, the growth of these mural and polar fragments was followed in vitro since numerous technical difficulties make an in vivo analysis of this problem impracticable. In a manner similar to the mouse, the isolated mural trophectoderm of the guinea pig stopped dividing and became giant. In contrast, guinea-pig polar fragments formed egg-cylinder-like structures. The latter contained regions structurally similar to two presumptive polar trophectodermal derivatives namely the ectoplacental and extraembryonic ectodermal tissues. These findings suggest that guinea-pig trophectodermal growth may occur in a manner similar to the mouse and thus be under ICM control.

scholarly journals Reversible neutralization by congo red of the anthracidal power of serum

1937 ◽  
Vol 37 (3) ◽  
pp. 471-473 ◽  
Author(s):  
J. Gordon ◽  
N. Wood
Keyword(s):  
Guinea Pig ◽  
Congo Red ◽  
Inhibitory Action ◽  
Protein Solutions ◽  
Haemolytic Activity ◽  
In Vitro Experiments ◽  
Serum Complement ◽  
Destructive Effect

In earlier papers (Gordon, 1930) it was shown that congo red has an inactivating effect on serum complement, both haemolytic and bactericidal, and that this effect can be reversed by treating the serum and congo red mixture with charcoal, the charcoal removing the congo red and leaving the complement active again. A similar reversal of inactivation is obtained by using instead of the charcoal, heated serum (55° C. for 30 min.) or protein solutions. Later (Gordon, 1931), it was shown that congo red had an inactivating effect on the haemolysins of Streptococcus haemolyticus and B. welchii. The reversibility of this effect was not so easy to demonstrate as with complement. Charcoal had a destructive effect on the haemolysins and so could not be used. It was found, however, that when the concentration of congo red was just sufficient to neutralize the streptococcal haemolysin, the addition of cuprammonium artificial silk adsorbed the congo red and liberated the haemolysin. In the case of B. welchii this method of reversal was not suitable, as the artificial silk had a destructive effect on the haemolysin. Instead, reversibility was demonstrated by adding ox serum to the mixture of congo red and haemolysin. This brought about a redistribution of the congo red between the ox serum and the haemolysin and if the amount of congo red used had been only just sufficient to neutralize the haemolysin of B. welchii, then the haemolytic activity could again be demonstrated. Gordon and Robson (1933) showed that congo red interfered with the anaphylactic reaction tested both in vivo and in vitro, the guinea-pig uterus being used in the in vitro experiments, in which the inhibitory action of the dye was shown to be reversible. It was suggested that the congo red interfered with the entrance of antigen into the cell.

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