The Inotropic and Chronotropic Responses of the Guinea Pig and Dog Myocardium to Isoprenaline and Salbutamol

1975 ◽  
Vol 53 (2) ◽  
pp. 231-238 ◽  
Author(s):  
R. L. Hughson ◽  
J. R. Ledsome
Keyword(s):  
Guinea Pig ◽  
Adrenergic Receptors ◽  
Response Pattern ◽  
Inotropic Response ◽  
Dog Heart ◽  
Relative Response ◽  
Guinea Pig Atrium ◽  
Inotropic Responses

The relative effects of isoprenaline and salbutamol on the inotropic and chronotropic responses of the denervated myocardium of the chloralose anesthetized dog and of the isolated guinea pig atrium, and the inotropic response of the isolated dog papillary muscle were studied. Both the in vivo dog heart and the in vitro guinea pig atrium displayed a similar relative response pattern to isoprenaline and salbutamol with regard to their inotropic and chronotropic responses. However, a comparison of the relative inotropic responses of the dog heart in vivo and in vitro showed that in vitro, salbutamol has a much lower affinity and efficacy for the adrenergic receptors than isoprenaline.

Airway transepithelial electric potential in vivo: species and regional differences

1980 ◽  
Vol 48 (1) ◽  
pp. 169-176 ◽  
Author(s):  
R. C. Boucher ◽  
P. A. Bromberg ◽  
J. T. Gatzy
Keyword(s):  
Guinea Pig ◽  
Regional Differences ◽  
Response Pattern ◽  
Bioelectric Potential ◽  
Liquid Junction ◽  
Airway Epithelia ◽  
Subcutaneous Space ◽  
Liquid Junction Potentials

A technique for measurement of transmural bioelectric potential difference (PD) in vivo was adapted for use in mammalian airways. PD was measured between a Ringer-perfused exploring bridge positioned on the airway furface and a reference Ringer-agar bridge in the subcutaneous space. The in vivo PD of canine trachea from 50 dogs was 30.8 +/- 9.5 (SD) mV, lumen negative, indistinguishable from the peak in vitro transmural PD of the excised canine trachea. Liquid junction potentials between bridge perfusate and tracheal liquid were negligible. The response pattern to drugs applied to the mucosal surface in vivo was similar to that observed in vitro. The PD in canine bronchi 3-6 cm distal to the carina were substantially lower. Tracheal PDs of rabbit (-23 mV), guinea pig (-8 mV), and rat (-14 mV) were higher than bronchial PDs of the same species. PD across airway epithelia can be accurately and reliably measured in vivo and the lower bronchial PD suggests regional differences in electrolyte transport and/or permeability.

A positive inotropic response of guinea pig isolated atria to histamine not mediated via H1 or H2 receptors

1980 ◽  
Vol 58 (2) ◽  
pp. 167-173 ◽  
Author(s):  
Campbell Wilson ◽  
Kenneth J. Broadley
Keyword(s):  
Guinea Pig ◽  
Adrenergic Receptors ◽  
Inotropic Response ◽  
Positive Component ◽  
Response Curves ◽  
H2 Receptors ◽  
Isolated Atria ◽  
Inotropic Responses ◽  
Β Adrenergic Receptors ◽  
Right Atria

The positive chronotropic responses of guinea pig isolated right atria to histamine were antagonized by metiamide (pA2, 5.95) thus confirming their H2 receptor classification. The positive inotropic responses of paced left atria were antagonized to some extent by mepyramine to give a pA2 value of 7.87, indicating the involvement of H1 receptors. A limit to the shift of cumulative dose–response curves for the inotropic response suggested an H1 receptor resistant component. The inotropic response to sequentially administered histamine was biphasic. On lowering the temperature to 25 °C, the two components became more demarcated and separated by a negative phase. Only the primary positive component and the negative component were antagonized by mepyramine. At 38 °C, the response was similarly converted to a monophasic one. The residual responses were resistant to metiamide and propranolol antagonism and therefore not mediated via H1, H2, or β-adrenergic receptors.

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.

scholarly journals Norepinephrine Protects against Methamphetamine Toxicity through β2-Adrenergic Receptors Promoting LC3 Compartmentalization

2021 ◽  
Vol 22 (13) ◽  
pp. 7232
Author(s):  
Gloria Lazzeri ◽  
Carla L. Busceti ◽  
Francesca Biagioni ◽  
Cinzia Fabrizi ◽  
Gabriele Morucci ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Light Chain ◽  
Adrenergic Receptors ◽  
Cell Damage ◽  
Protective Effects ◽  
Autophagy Flux ◽  
Brain Areas ◽  
Indirect Consequence

Norepinephrine (NE) neurons and extracellular NE exert some protective effects against a variety of insults, including methamphetamine (Meth)-induced cell damage. The intimate mechanism of protection remains difficult to be analyzed in vivo. In fact, this may occur directly on target neurons or as the indirect consequence of NE-induced alterations in the activity of trans-synaptic loops. Therefore, to elude neuronal networks, which may contribute to these effects in vivo, the present study investigates whether NE still protects when directly applied to Meth-treated PC12 cells. Meth was selected based on its detrimental effects along various specific brain areas. The study shows that NE directly protects in vitro against Meth-induced cell damage. The present study indicates that such an effect fully depends on the activation of plasma membrane β2-adrenergic receptors (ARs). Evidence indicates that β2-ARs activation restores autophagy, which is impaired by Meth administration. This occurs via restoration of the autophagy flux and, as assessed by ultrastructural morphometry, by preventing the dissipation of microtubule-associated protein 1 light chain 3 (LC3) from autophagy vacuoles to the cytosol, which is produced instead during Meth toxicity. These findings may have an impact in a variety of degenerative conditions characterized by NE deficiency along with autophagy impairment.

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 Roles of GP33, a guinea pig cytomegalovirus-encoded G protein-coupled receptor homolog, in cellular signaling, viral growth and inflammation in vitro and in vivo

2018 ◽  
Vol 14 (12) ◽  
pp. e1007487 ◽  
Author(s):  
Miei Takeda ◽  
Shinji Watanabe ◽  
Harutaka Katano ◽  
Kazuma Noguchi ◽  
Yuko Sato ◽  
...  
Keyword(s):  
Guinea Pig ◽  
G Protein ◽  
Cellular Signaling ◽  
G Protein Coupled Receptor ◽  
Viral Growth ◽  
Guinea Pig Cytomegalovirus ◽  
G Protein Coupled

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.

Sign in / Sign up

Export Citation Format

Share Document