The Role of P2 Receptor-Mediated Component in Neurogenic Tone Control of Human Great Saphenous Vein

Abstract

The aim of the investigation was to evaluate experimentally the role of the P2 receptor-mediated component in neurogenic tone control of human varicose-affected and healthy great saphenous vein (GSV).Materials and Methods. The material for the study were segments of GSV obtained from two groups of patients: group 1 (n=14) included patients with varicose vein disease, in whom GSV was removed during surgical treatment; group 2 (n=21) comprised patients with coronary artery disease who underwent coronary artery bypass grafting using GSV as an autograft. Mechanical activity of the isolated veins was studied in vitro by electrical stimulation before and after incubation with atropine and phentolamine, pyridoxal-phosphate-6-azophenyl-2',4'-disulfonate (PPADS) and suramin (both nonselective antagonists of P2 receptors), and also after desensitization of P2X receptors by α,β-methylene ATP.Results. Atropine and phentolamine did not completely inhibit the contractile responses evoked by electric field stimulation of the varicose and non-varicose GSV. PPADS (10 and 30 μМ) and suramin (100 and 300 μМ) significantly reduced the contractile amplitude of GSV response in both groups of veins (p<0.05) in the presence of atropine and phentolamine. α,β-methylene ATP (10 μМ) did not significantly reduce the amplitude of the GSV contractile response (p>0.05). Atropine, phentolamine and PPADS inhibited the contractile responses to a lesser extent in the varicose-affected veins compared to the veins unaffected by varicose disease.Conclusion. These experimental results suggest the presence of the P2 receptor-mediated component in the neurogenic control of human GSV tone. Further studies of the P2 receptor mechanism of action is promising for the development of drugs both for treating varicose veins and for preventing spasm of the venous grafts after aortocoronary bypass surgery.