Back to Search
Start Over
Adenosine A2a-receptor activation increases contractility in isolated perfused hearts
- Source :
- American Journal of Physiology-Heart and Circulatory Physiology. 279:H1472-H1481
- Publication Year :
- 2000
- Publisher :
- American Physiological Society, 2000.
-
Abstract
- Adenosine A2a-receptor activation enhances shortening of isolated cardiomyocytes. In the present study the effect of A2a-receptor activation on the contractile performance of isolated rat hearts was investigated by recording left ventricular pressure (LVP) and the maximal rate of LVP development (+dP/d tmax). With constant-pressure perfusion, adenosine caused concentration-dependent increases in LVP and +dP/d tmax, with detectable increases of 4.1 and 4.8% at 10−6M and maximal increases of 12.0 and 11.1% at 10−4M, respectively. The contractile responses were prevented by the A2a-receptor antagonists chlorostyryl-caffeine and aminofuryltriazolotriazinyl-aminoethylphenol (ZM-241385) but were not affected by the β1-adrenergic antagonist atenolol. The adenosine A1-receptor antagonist dipropylcyclopentylxanthine and pertussis toxin potentiated the positive inotropic effects of adenosine. The A2a-receptor agonists ethylcarboxamidoadenosine and dimethoxyphenyl-methylphenylethyl-adenosine also enhanced contractility. With constant-flow perfusion, 10−5M adenosine increased LVP and +dP/d tmaxby 5.5 and 6.0%, respectively. In the presence of the coronary vasodilator hydralazine, adenosine increased LVP and +dP/d tmaxby 7.5 and 7.4%, respectively. Dipropylcyclopentylxanthine potentiated the adenosine contractile responses with constant-flow perfusion in the absence and presence of hydralazine. These increases in contractile performance were also antagonized by chlorostyryl-caffeine and ZM-241385. The results indicate that adenosine increases contractile performance via activation of A2areceptors in the intact heart independent of β1-adrenergic receptor activation or changes in coronary flow.
- Subjects :
- Male
medicine.medical_specialty
Adenosine
Receptor, Adenosine A2A
Physiology
Vasodilator Agents
Adrenergic beta-Antagonists
Adenosine A2A receptor
Adenosine-5'-(N-ethylcarboxamide)
In Vitro Techniques
Biology
Rats, Sprague-Dawley
Contractility
Adenosine A1 receptor
β1 adrenergic receptor
Physiology (medical)
Internal medicine
Pressure
Purinergic P1 Receptor Agonists
medicine
Animals
Virulence Factors, Bordetella
Receptors, Purinergic P1
Drug Synergism
Heart
Hydralazine
Myocardial Contraction
Rats
Perfusion
Vasodilation
Endocrinology
Atenolol
Pertussis Toxin
Purinergic P1 Receptor Antagonists
Xanthines
Circulatory system
Cardiology and Cardiovascular Medicine
medicine.drug
Subjects
Details
- ISSN :
- 15221539 and 03636135
- Volume :
- 279
- Database :
- OpenAIRE
- Journal :
- American Journal of Physiology-Heart and Circulatory Physiology
- Accession number :
- edsair.doi.dedup.....0fcd23ff4e06f642ca294e786b08fd36