Vascular impairment of adenosinergic system in hypertension: increased adenosine bioavailability and differential distribution of adenosine receptors and nucleoside transporters.

Adenosinergic system regulates vascular tonicity through the complex system of adenosine, adenosine receptors (ARs) and nucleoside transporters. This work aimed at evaluating the impact of hypertension on adenosine bioavailability and expression/distribution profile of AR subtypes (A, A, A, A) and equilibrative nucleoside transporters (ENT1, ENT2, ENT3, ENT4). Adenosine was measured in vascular tissue extracts by HPLC (fluorescence detection); immunoreactivities (ARs/ENTs) in mesenteric arteries/veins from normotensive Wistar Kyoto (WKY) and spontaneously hypertensive rats (SHR) were analyzed by histomorphometry.