title: Functional evidence for the presence of adenosine A2-receptors in cultured coronary endothelial cells.
abstract: 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.
authors.forename: C
authors.initials: C
authors.lastname: Des Rosiers
authors.forename: S
authors.initials: S
authors.lastname: Nees
mesh_terms: 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
chemical_list: D011983:Receptors, Purinergic; D014970:Xanthines; C008514:methylxanthine; D019830:Adenosine-5'-(N-ethylcarboxamide); D000242:Cyclic AMP; D000225:Adenine; D000241:Adenosine