Comparison of the effects of EDRF on calcium-activated potassium channels of mesenteric artery smooth muscle between patients with essential hypertension and normotensive patients / 中国实用内科杂志

ABSTRACT

Objective To study the effects of Nitric oxide(NO),Nitric oxide synthases (NOS)on calcium-activated potassium channels (KCa) of mesenteric artery smooth muscle(SMC)between patients with essential hypertension (EH) and normotensive patients.Methods (1)Mesenteric artery branch from 21 EH and 18 normotensive patients respectively was digested by enzyme.Patch clamp technique was used to pull cell-attached and inside-out patches on mesenteric artery SMC from EH.The signal channel open number probability (Po),open dwell-time(To) and close dwell- time(Tc),were recorded.(2)The levels of plasma NO?NOS were measured by colorimetry analysis method.(3)The analysis of linear correlation was performed to estimate the relationship between the levels of plasma NO and Po?To?Tc of KCa of mesenteric artery SMC in the subjects of the two groups.Results (1)Compared to that of normotensive patients,the activities of KCa channels of patients with EH was higher.After adding Ca 2+ to cytoplasm,the Po of KCa channels in normotensive patients increased significantly.But there were few changes in EH group.(2)The levels of plasma NO?NOS were lower in EH group than in control group.(3)Linear correlation analysis showed that the levels of plasma NO were correlated positively with Po?To in normotensive patients,wherese the positive correlation were decreased in EH group.Conclusion The activities of KCa channels of patients with EH increase significantly.but the sensitivity to Ca 2+ decreased.NO?NOS may stimulate the KCa channels of normotensive and EH patients,but they may not be main factors in EH patients.