OBJECTIVES: To assess the sensitivity of saphenous vein to @entity972 channel opening drugs (KCOs). METHODS: Saphenous vein, harvested at bypass surgery or high ligation for correction of varicose veins, was exposed to an in vitro flow circuit and vasomotor responses assessed by organ bath pharmacology. OUTCOME MEASURES: Effective drug concentrations for 50% reduction in vein ring tension (IC50). RESULTS: Vein rings pre-contracted with @entity2647 showed a concentration-dependent relaxation to all the KCOs tested with a potency ranking of @entity69404 > @entity31802 > @entity1706 > @entity6335 . The relaxation to cromakalim was endothelium-independent and was inhibited by @entity5217 (an @entity855 -sensitive K+ channel blocker). The sensitivity of vein rings to cromakalim increased after exposure to arterial flow conditions for 90 minutes (IC50 before 1.7 +/- 0.25 microM and after 0.25 +/- 0.08 microM, p > 0.001). This effect was not evident after 90 min of venous flow conditions, 2.19 +/- 0.49 microM. When the workload on vein, exposed to arterial flow conditions, was reduced mechanically by external stenting with PTFE the increased sensitivity to cromakalim was abolished. CONCLUSIONS: Saphenous vein has @entity855 -sensitive K+ channels responsive to KCOs. The increased sensitivity to cromakalim, induced by arterial flow conditions, may represent an endogenous protective mechanism limiting @entity16 resulting from the higher workload imposed on grafted vein.

The effects of XXXX channel openers on saphenous vein exposed to arterial flow.

@entity31802 :: ('MESH:D019806', 'Chemical') :: ['cromakalim'] @entity6335 :: ('MESH:D003981', 'Chemical') :: ['diazoxide'] @entity5217 :: ('MESH:D005905', 'Chemical') :: ['glibenclamide'] @entity16 :: ('MESH:D009422', 'Disease') :: ['ischaemic damage'] @entity855 :: ('MESH:D000255', 'Chemical') :: ['ATP'] @entity2647 :: ('MESH:D010656', 'Chemical') :: ['phenylephrine'] @entity69404 :: ('MESH:C075012', 'Chemical') :: ['HOE 234'] @entity972 :: ('MESH:D011188', 'Chemical') :: ['potassium'] @entity1706 :: ('MESH:D020110', 'Chemical') :: ['pinacidil']
@entity972 :: (MESH:D011188,Chemical) :: ['potassium']
