Functional evidence for the presence of adenosine A2-receptors in cultured coronary endothelial cells.
Adenosine and the adenosine receptor agonists, R- and S-N6-phenylisopropyladenosine (R- and S-PIA) and 5'-N-ethylcarboxamidoadenosine (NECA), enhanced [3H]cAMP accumulation in [3H]adenine-labelled cultured endothelial cells isolated from the microvasculature of guinea pig hearts. As shown by their concentration-response curves, NECA was a more potent agonist than R-PIA or adenosine. Their respective concentrations at half-maximal stimulation of [3H]cAMP accumulation were 0.7 microM, 10.5 microM and 12.6 microM, indicating a 15- to 18-fold potency difference between NECA and the other agonists. The increased [3H]cAMP accumulation elicited by 10(-5) M NECA was inhibited by the xanthine derivative 8-phenyltheophylline, 3-isobutyl-1-methylxanthine, theophylline or caffeine. These findings provide functional evidence for the presence of adenosine receptors of the A2-type in microvascular coronary endothelial cells in culture. The functional significance of these receptors remains to be established, but they may be involved in the regulation of vascular permeability.
Des Rosiers
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Nees
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D000225:Adenine / Q000378:metabolism; D000241:Adenosine / Q000031:analogs & derivatives / Q000494:pharmacology; D019830:Adenosine-5'-(N-ethylcarboxamide); D000818:Animals; D002478:Cells, Cultured; D003331:Coronary Vessels / Q000166:cytology / Q000378:metabolism*; D000242:Cyclic AMP / Q000378:metabolism; D004727:Endothelium / Q000166:cytology; D006168:Guinea Pigs; D066298:In Vitro Techniques; D009131:Muscle, Smooth, Vascular / Q000378:metabolism*; D011983:Receptors, Purinergic / Q000378:metabolism*; D014970:Xanthines / Q000494:pharmacology
D011983:Receptors, Purinergic; D014970:Xanthines; C008514:methylxanthine; D019830:Adenosine-5'-(N-ethylcarboxamide); D000242:Cyclic AMP; D000225:Adenine; D000241:Adenosine