RESUMEN
AIM:To investigate the mechanism of quercetin improving rat coronary artery myogenic response under high glucose ( HG) by measuring muscle tension of coronary arterial ring and recording voltage -gated K +channel ( Kv) current of coronary artery smooth muscle cells by whole cell patch clamp .METHODS:The coronary rings from the normal SD rats were acutely isolated , and then divided into 6 groups:(1) control group;(2) HG group;(3) HG+low dose (3 μmol/L) of quercetin group;(4) HG+moderate dose (10 μmol/L) of quercetin group; (5) HG+high dose (30 μmol/L) of quercetin group;(6) HG+C6303 (PKC inhibitor) +high dose of quercetin group.Determinations of coronary artery response to vasoconstrictor (60 mmol/L KCl or 0.1 mmol/L U46619) or vasodilator (Ach at 10 -9 ~10 -5 mol/L) were performed, and the percentage of coronary ring tension was calculated using the contraction as 100%caused by 60 mmol/L KCl.The rat coronary artery smooth muscle cells were acutely isolated for recording the Kv current using whole cell patch clamp .RESULTS:Compared with control group , the contraction amplitudes to 60 mmol/L KCl or 0.1 mmol/L U46619 were significantly increased under HG incubation .Quercetin intervention concentration-dependently re-duced the coronary artery contraction amplitude .Incubation of PKC specific inhibitor C 6303 attenuated the effect of querce-tin.Compared with control group , the diastolic amplitude to Ach decreased significantly in HG group , and quercetin inter-vention concentration-dependently increased the coronary artery diastolic amplitude .Incubation of PKC specific inhibitor C6303 attenuated the effect of quercetin .Compared with control group , HG incubation inhibited Kv current of coronary ar-tery vascular smooth muscle cells significantly , and quercetin intervention attenuated the inhibitory effect of HG on Kv cur-rent intensity .Incubation of PKC specific inhibitor C 6303 attenuated the effect of quercetin .CONCLUSION: Quercetin has a protective effect on myogenic response of coronary artery under HG and the effects is related to the increase in Kv cur -rent and the activation of PKC in vascular smooth muscle cells .
RESUMEN
AIM:To investigate the mechanism of quercetin improving rat coronary artery myogenic response under high glucose ( HG) by measuring muscle tension of coronary arterial ring and recording voltage -gated K +channel ( Kv) current of coronary artery smooth muscle cells by whole cell patch clamp .METHODS:The coronary rings from the normal SD rats were acutely isolated , and then divided into 6 groups:(1) control group;(2) HG group;(3) HG+low dose (3 μmol/L) of quercetin group;(4) HG+moderate dose (10 μmol/L) of quercetin group; (5) HG+high dose (30 μmol/L) of quercetin group;(6) HG+C6303 (PKC inhibitor) +high dose of quercetin group.Determinations of coronary artery response to vasoconstrictor (60 mmol/L KCl or 0.1 mmol/L U46619) or vasodilator (Ach at 10 -9 ~10 -5 mol/L) were performed, and the percentage of coronary ring tension was calculated using the contraction as 100%caused by 60 mmol/L KCl.The rat coronary artery smooth muscle cells were acutely isolated for recording the Kv current using whole cell patch clamp .RESULTS:Compared with control group , the contraction amplitudes to 60 mmol/L KCl or 0.1 mmol/L U46619 were significantly increased under HG incubation .Quercetin intervention concentration-dependently re-duced the coronary artery contraction amplitude .Incubation of PKC specific inhibitor C 6303 attenuated the effect of querce-tin.Compared with control group , the diastolic amplitude to Ach decreased significantly in HG group , and quercetin inter-vention concentration-dependently increased the coronary artery diastolic amplitude .Incubation of PKC specific inhibitor C6303 attenuated the effect of quercetin .Compared with control group , HG incubation inhibited Kv current of coronary ar-tery vascular smooth muscle cells significantly , and quercetin intervention attenuated the inhibitory effect of HG on Kv cur-rent intensity .Incubation of PKC specific inhibitor C 6303 attenuated the effect of quercetin .CONCLUSION: Quercetin has a protective effect on myogenic response of coronary artery under HG and the effects is related to the increase in Kv cur -rent and the activation of PKC in vascular smooth muscle cells .
RESUMEN
Voltage-gated K+ (Kv) channels have been considered to be a regulator of membrane potential and neuronal excitability. Recently, accumulated evidence has indicated that several Kv channel subtypes contribute to the control of cell proliferation in various types of cells and are worth noting as potential emerging molecular targets of cancer therapy. In the present study, we investigated the effects of the Kv1.1-specific blocker, dendrotoxin-kappa (DTX-kappa), on tumor formation induced by the human lung adenocarcinoma cell line A549 in a xenograft model. Kv1.1 mRNA and protein was expressed in A549 cells and the blockade of Kv1.1 by DTX-kappa, reduced tumor formation in nude mice. Furthermore, treatment with DTX-kappa significantly increased protein expression of p21Waf1/Cip1, p27Kip1, and p15INK4B and significantly decreased protein expression of cyclin D3 in tumor tissues compared to the control. These results suggest that DTX-kappa has anti-tumor effects in A549 cells through the pathway governing G1-S transition.