Experimental studies on contractile effects of varicose and nonvaricose human saphenous veins

Method: Contractile responses of isolated human saphenous veins to agonists with different mode of action were investigated. Rings (2-3 mm in length) were placed in an organ bath for isometric tension recording. Veins were ob tained from patients after saphenectomy or bypass operations. Result: The m ost potent agonists were endothelin-1 and thromboxane A(2) (as U 46619) fol lowed by 5-HT and noradrenaline. At nanomolar concentrations angiotensin ii caused a weak contractile effect. To characterize the receptors selective antagonists were used. Compared to nonvaricose veins the contractile respon se of varicose veins was significantly diminished. With increasing age of t he patients the contractile forces decreases independent of the agonists us ed and the affinity for the receptors. Conclusion: Disturbances in the sign al transduction pathways or morphological changes may contribute to the age -dependent contractile responses.