Document Detail

Quantification of the in vivo potency of the adenosine A2 receptor antagonist 8-(3-chlorostyryl)caffeine.
MedLine Citation:
PMID:  7562557     Owner:  NLM     Status:  MEDLINE    
The purpose of the present study was to quantify the in vivo potency of the selective adenosine A2a antagonist CSC [8-(3-chlorostyryl)caffeine]. Four groups of conscious, normotensive rats received a continuous i.v. infusion of 0, 6, 12 and 24 micrograms/min/kg of CSC. During a steady-state infusion of CSC, the animals received 1000 micrograms/kg of the adenosine A2a receptor agonist CGS 21680C [the sodium salt of 2-p-(2-carboxyethyl) phenylethylamino-5'-N-ethylcarboxamidoadenosine] i.v. over 15 min. During the experiment, the mean arterial pressure and the heart rate were recorded continuously and arterial blood samples were taken for the analysis of drug concentrations. For each individual rat, the CGS 21680C-provoked reduction in blood pressure was related to the blood concentration of the agonist according to the sigmoidal Emax model. The presence of CSC produced a parallel shift of the concentration-hypotensive effect curve to the right, indicating competitive interaction of the compounds. Infusion of 0, 6, 12 and 24 micrograms/min/kg of CSC resulted in steady-state concentrations of 0, 85 +/- 7, 210 +/- 20 and 400 +/- 40 ng/ml, and apparent EC50 values of CGS 21680C based on free concentrations (EC50,u) of 4.8 +/- 1.1, 7.2 +/- 0.5, 32 +/- 6 and 57 +/- 10 ng/ml, respectively (mean +/- S.E., n = 6, 6, 5 and 6). The relationship between the CSC concentration and the apparent EC50 was quantified according to a competitive pharmacodynamic interaction model.(ABSTRACT TRUNCATED AT 250 WORDS)
R A Mathôt; J M Gubbens-Stibbe; W Soudijn; K A Jacobson; A P Ijzerman; M Danhof
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Publication Detail:
Type:  Comparative Study; Journal Article    
Journal Detail:
Title:  The Journal of pharmacology and experimental therapeutics     Volume:  275     ISSN:  0022-3565     ISO Abbreviation:  J. Pharmacol. Exp. Ther.     Publication Date:  1995 Oct 
Date Detail:
Created Date:  1995-11-21     Completed Date:  1995-11-21     Revised Date:  2013-02-25    
Medline Journal Info:
Nlm Unique ID:  0376362     Medline TA:  J Pharmacol Exp Ther     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  245-53     Citation Subset:  IM    
Division of Pharmacology, Leiden/Amsterdam Center for Drug Research, University of Leiden, The Netherlands.
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MeSH Terms
Adenosine / analogs & derivatives*,  pharmacokinetics,  pharmacology
Antihypertensive Agents / pharmacokinetics,  pharmacology
Blood Pressure / drug effects
Caffeine / analogs & derivatives*,  pharmacokinetics,  pharmacology
Drug Evaluation, Preclinical
Drug Interactions
Heart Rate / drug effects
Phenethylamines / pharmacokinetics,  pharmacology*
Purinergic P1 Receptor Agonists*
Purinergic P1 Receptor Antagonists*
Grant Support
Reg. No./Substance:
0/Antihypertensive Agents; 0/Phenethylamines; 0/Purinergic P1 Receptor Agonists; 0/Purinergic P1 Receptor Antagonists; 120225-54-9/2-(4-(2-carboxyethyl)phenethylamino)-5'-N-ethylcarboxamidoadenosine; 148589-13-3/8-(3-chlorostyryl)caffeine; 58-08-2/Caffeine; 58-61-7/Adenosine

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