IDENTIFICATION OF ADENOSINE A(2) RECEPTOR CAMP SYSTEM IN HUMAN AORTIC ENDOTHELIAL-CELLS

The involvement of endothelial adenosine A(2) receptor-cAMP system in A(2) receptor-mediated vasodilation in human aortic endothelial cells (HAEC) was investigated. Reverse transcription-polymerase chain reaction (RT-PCR) revealed the expression of both A(2a) and A(2b) receptors mRNA in HAEC. In HAEC, YT-146 (selective A(2) receptor-agonist) produced a dose dependent increase of cAMP production. This increase was inhibited by theophylline. YT-146 also showed a vasodilatory action in isolated rat aorta. The removal of endothelium significantly attenuated this vasodilatory effect. Our results provide the first evidence for the expression of both subtypes of the A(2a) and A(2b) receptors which regulate cAMP production in human endothelial cells. The present results also suggest that A(2) receptor-cAMP system was involved in the endothelium-dependent vasodilatory actions and may play important roles in regulating vascular functions of HAEC. (C) 1994 Academic Press, Inc.