Types of potassium channels involved in the resveratrol's effects on vascular tone of diabetic patients

Background and Aims : Altered vascular tone in prolonged hyperglycemia is mainly due to endothelial impairment and changes in the functionality of smooth muscle potassium channels (SMPC). However, the fact that resveratrol (RSV) is able to cause relaxation of those vessels, poses intriguing lights in the cellular target sites at which it acts in pathological conditions. Our aim was to give an overview at the types of SMPK involved in the mechanism of RSV action in diabetic patients.Methods: Samples of human saphenous vein (HSV) were taken after coronary arteries bypass grafting (CABG) of patients with DMT2, mounted in an organ bath system and relaxed by increasing concentrations of RSV (1-100 μM).Results: A highly selective Kv1.2/Kv1.3 and Kv4.2/Kv4.3-channels blockers, margatoxin (MgTx) and phrixotoxin-2 (PhTx) did not significantly modified the vasorelaxant effect of RSV on the HSV from patients with DMT2 (n = 5 both, pD2 = 4.8 ± 0.3 in the presence vs. 4.5 ± 0.42 in the absence of PhTx; pD2 = 4.6 ± 0.2 in the presence vs. 4.8 ± 0.3 in the absence of MgTx, p > 0.05 both). On contrary, highly selective big Ca2+ activated K+ channel blocker, iberiotoxin (IbTx) significantly modified aforementioned effects of RSV (n = 5 both, pD2 = 4.3 ± 0.3 in the presence vs. 4.8 ± 0.3 in the absence of IbTx, p < 0.05).Conclusions: It seems that MgTx and PhTx sensitive SMVC are not involved in the relaxant effects of RSV on HSV from diabetic patients, in contrast with the channels sensitive to IbTx. Background and Aims : Altered vascular tone in prolonged hyperglycemia is mainly due to endothelial impairment and changes in the functionality of smooth muscle potassium channels (SMPC). However, the fact that resveratrol (RSV) is able to cause relaxation of those vessels, poses intriguing lights in the cellular target sites at which it acts in pathological conditions. Our aim was to give an overview at the types of SMPK involved in the mechanism of RSV action in diabetic patients. Methods: Samples of human saphenous vein (HSV) were taken after coronary arteries bypass grafting (CABG) of patients with DMT2, mounted in an organ bath system and relaxed by increasing concentrations of RSV (1-100 μM). Results: A highly selective Kv1.2/Kv1.3 and Kv4.2/Kv4.3-channels blockers, margatoxin (MgTx) and phrixotoxin-2 (PhTx) did not significantly modified the vasorelaxant effect of RSV on the HSV from patients with DMT2 (n = 5 both, pD2 = 4.8 ± 0.3 in the presence vs. 4.5 ± 0.42 in the absence of PhTx; pD2 = 4.6 ± 0.2 in the presence vs. 4.8 ± 0.3 in the absence of MgTx, p > 0.05 both). On contrary, highly selective big Ca2+ activated K+ channel blocker, iberiotoxin (IbTx) significantly modified aforementioned effects of RSV (n = 5 both, pD2 = 4.3 ± 0.3 in the presence vs. 4.8 ± 0.3 in the absence of IbTx, p < 0.05). Conclusions: It seems that MgTx and PhTx sensitive SMVC are not involved in the relaxant effects of RSV on HSV from diabetic patients, in contrast with the channels sensitive to IbTx.