THE HUMAN SAPHENOUS-VEIN IN PHARMACOLOGY - EFFECT OF A NEW MICRONIZEDFLAVONOIDIC FRACTION (DAFLON 500 MG) ON NOREPINEPHRINE-INDUCED CONTRACTION

Local acidosis (pH 6.4) depresses reactivity of vascular smooth muscle and especially the response of human isolated saphenous veins to exog enous norepinephrine. Experiments were performed to study, under acido sis conditions, the interaction between Daflon 500 mg, a micronized fr action of 90% diosmin and 10% hesperidin, and norepinephrine on human rings of veins. Varicose veins were obtained by conservative varicose veins surgery and normal veins from patients undergoing coronary arter y bypass graft surgery. Isometric tension was recorded from venous rin gs in organ chambers filled with Krebs-Henseleit solution (pH 7.4; 37 degrees C). Metabolic acidosis (from pH 7.4 to 6.4) was obtained by lo wering the HCO3- concentration of the Krebs-Henseleit solution. Cumula tive concentration-response curves for norepinephrine (10(-7) to 10(-5 )M) were obtained at pH 6.4 in the presence or in the absence of Daflo n 500 mg (10(-5)M) added 20 min previously to the organ bath. Under ac idotic conditions, Daflon 500 mg induced a shift to the left of the co ncentration-response curves for norepinephrine. This potentiation was significant in both normal and varicose veins and was increased in pro portion with the pathological status of the venous rings. These result s support the therapeutic benefits of Daflon 500 mg in chronic venous insufficiency.