Affiliations: Institute of Clinical Medicine, University of Siena, School of Medicine, I-53100 Siena, Italy
Abstract: The effect of i.v. infusion of adenosine (20/μg/kg/min over 10 min + 40/μg/kg/min over 10 min) on peripheral haemodynamics, blood rheology and platelet aggregation has been studied in 8 volunteers. Blood pressure, heart rate, rest flow at the lower limbs, blood viscosity, whole blood filterability, haemoglobin affinity for O2 (P50), 2,3-diphosphoglycerate (2,3-DPG), platelet aggregation were measured. Free cytosolic calcium levels were evaluated in platelets in resting conditions and after in vitro stimulation. Plasma adenosine levels were detected by HPLC. Adenosine infusion did not induce significant changes in rest flow, blood pressure and heart rate. At the end of infusion a significant reduction in blood viscosity (p<0.01) with a concomitant significant increase of blood filterability (p<0.05) was observed. P50 and 2,3-DPG tended to increase at the end of infusion as an expression of reduced haemoglobin affinity for O2 potentially associated to an increased delivery of O2 to peripheral tissues. Adenosine induced a significant reduction of platelet aggregability (p<0.01) with a decrease of free cytosolic calcium levels. In conclusion adenosine induces a series of biological changes possibly useful at the microcirculatory level at infusion rates that are well tolerated and devoid of significant haemodynamic effect.
