Adenosine deaminase inhibition enhances the inotropic response mediated by A1 adenosine receptor in hyperthyroid guinea pig atrium

2007 ◽  
Vol 56 (2) ◽  
pp. 124-131 ◽  
Author(s):  
A KEMENYBEKE ◽  
A JAKAB ◽  
J ZSUGA ◽  
M VECSERNYES ◽  
D KARSAI ◽  
...  
Keyword(s):  
Guinea Pig ◽  
Adenosine Deaminase ◽  
Adenosine Receptor ◽  
Inotropic Response ◽  
A1 Adenosine Receptor ◽  
Guinea Pig Atrium

scholarly journals An Advanced in Silico Modelling of the Interaction between FSCPX, an Irreversible A1 Adenosine Receptor Antagonist, and NBTI, a Nucleoside Transport Inhibitor, in the Guinea Pig Atrium

Molecules ◽  
2019 ◽  
Vol 24 (12) ◽  
pp. 2207 ◽  
Author(s):  
Adrienn Monika Szabo ◽  
Tamas Erdei ◽  
Gabor Viczjan ◽  
Rita Kiss ◽  
Judit Zsuga ◽  
...  
Keyword(s):  
Guinea Pig ◽  
Adenosine Receptor ◽  
In Silico ◽  
Ex Vivo ◽  
Nucleoside Transport ◽  
A1 Adenosine Receptor ◽  
Adenosine Receptor Antagonist ◽  
Transport Inhibitor ◽  
Guinea Pig Atrium ◽  
Nucleoside Transport Inhibitor

In earlier studies, we generated concentration-response (E/c) curves with CPA (N6-cyclopentyladenosine; a selective A1 adenosine receptor agonist) or adenosine, in the presence or absence of S-(2-hydroxy-5-nitrobenzyl)-6-thioinosine (NBTI, a selective nucleoside transport inhibitor), and with or without a pretreatment with 8-cyclopentyl-N3-[3-(4-(fluorosulfonyl)-benzoyloxy)propyl]-N1-propylxanthine (FSCPX, a chemical known as a selective, irreversible A1 adenosine receptor antagonist), in isolated, paced guinea pig left atria. Meanwhile, we observed a paradoxical phenomenon, i.e., the co-treatment with FSCPX and NBTI appeared to enhance the direct negative inotropic response to adenosine. In the present in silico study, we aimed to reproduce eight of these E/c curves. Four models (and two additional variants of the last model) were constructed, each one representing a set of assumptions, in order to find the model exhibiting the best fit to the ex vivo data, and to gain insight into the paradoxical phenomenon in question. We have obtained in silico evidence for an interference between effects of FSCPX and NBTI upon our ex vivo experimental setting. Regarding the mechanism of this interference, in silico evidence has been gained for the assumption that FSCPX inhibits the effect of NBTI on the level of endogenous (but not exogenous) adenosine. As an explanation, it may be hypothesized that FSCPX inhibits an enzyme participating in the interstitial adenosine formation. In addition, our results suggest that NBTI does not stop the inward adenosine flux in the guinea pig atrium completely.

scholarly journals Thyroid hormones decrease the affinity of 8-cyclopentyl-1,3-dipropylxanthine (CPX), a competitive antagonist, for the guinea pig atrial A1 adenosine receptor

2012 ◽  
Vol 31 (04) ◽  
pp. 389-400 ◽  
Author(s):  
Rudolf Gesztelyi ◽  
Zsuzsa Kiss ◽  
Judit Zsuga ◽  
Krisztian Pak ◽  
Csaba Papp ◽  
...  
Keyword(s):  
Guinea Pig ◽  
Thyroid Hormones ◽  
Adenosine Receptor ◽  
A1 Adenosine Receptor

scholarly journals Cloning and characterization of a pharmacologically distinct A1 adenosine receptor from guinea pig brain

1994 ◽  
Vol 26 (1-2) ◽  
pp. 143-155 ◽  
Author(s):  
Fan Meng Guo-xi Xie ◽  
Derek Chalmers ◽  
Caurnel Morgan ◽  
Stanley J. Watson ◽  
Huda Akil
Keyword(s):  
Guinea Pig ◽  
Adenosine Receptor ◽  
A1 Adenosine Receptor ◽  
Pig Brain ◽  
Guinea Pig Brain

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.

A1-adenosine receptor-mediated inhibition of adipocyte adenylate cyclase and lipolysis in Zucker rats

1989 ◽  
Vol 257 (6) ◽  
pp. E871-E878 ◽  
Author(s):  
S. J. Vannucci ◽  
C. M. Klim ◽  
L. F. Martin ◽  
K. F. LaNoue
Keyword(s):  
Adenylate Cyclase ◽  
Adenosine Deaminase ◽  
Adenosine Receptor ◽  
Lipolytic Activity ◽  
Hormonal Control ◽  
Zucker Rats ◽  
Camp Production ◽  
A1 Adenosine Receptor ◽  
Increased Sensitivity ◽  
A1 Receptor

Hormone-stimulated lipolysis is reduced in genetically obese rodents and may contribute to the increased adiposity characteristic of the obese state. Endogenously released adenosine, acting via the A1 receptor coupled to the inhibitory guanosine 5'-triphosphate binding protein, Gi, provides a tonic inhibition of lipolysis in rat adipocytes. Removal of this inhibition by the addition of adenosine deaminase frequently results in maximal lipolytic activity. Adipocytes isolated from lean Zucker (Fa/?) rats responded normally to adenosine deaminase, where lipolysis in adipocytes from obese Zucker (fa/fa) rats remained approximately 50% inhibited. Adipocyte adenylate cyclase was equally responsive to activation by forskolin, but lipolytic hormones were significantly less effective in stimulating adenosine 3',5'-cyclic monophosphate (cAMP) production in the obese adipocytes. These cells also exhibited an increased sensitivity to inhibition by the adenosine agonist, N6-(L-2-phenylisopropyl)-adenosine, either in combination with forskolin or beta-adrenergic hormone stimulation. Treatment of isolated adipocytes with pertussis toxin, which uncouples receptor-mediated Gi function, had little effect in cells from lean rats but increased isoproterenol stimulated cAMP production of cells from obese rats to levels observed in the lean cells. In addition, the adenosine A1 antagonist, 8-phenyltheophylline, increased cAMP and lipolytic activity in the obese adipocytes while having little significant effect in the lean adipocytes. These results suggest that hormonal control of lipolysis is altered in the obese Zucker rat because of an alteration in A1-adenosine receptor-mediated inhibition of adenylate cyclase.

scholarly journals Persistent Activation by and Receptor Reserve for an Irreversible A1-Adenosine Receptor Agonist in DDT1 MF-2 Cells and in Guinea Pig Heart

1997 ◽  
Vol 52 (3) ◽  
pp. 491-498 ◽  
Author(s):  
Jiahui Zhang ◽  
Luiz Belardinelli ◽  
Kenneth A. Jacobson ◽  
Deborah H. Otero ◽  
Stephen P. Baker
Keyword(s):  
Guinea Pig ◽  
Adenosine Receptor ◽  
Receptor Agonist ◽  
A1 Adenosine Receptor ◽  
Guinea Pig Heart ◽  
Receptor Reserve ◽  
Adenosine Receptor Agonist
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