Study on calcium-activated potassium channel of mesentery artery smooth muscle cells of hypertension patients / 中国应用生理学杂志

<p><b>AIM</b>To study the functional activity of K(cA) on human mesenteric artery smooth muscle cells (SMC) from essential hypertension (EH) patients.</p><p><b>METHODS</b>Patch clamp technique with Inside-out mode was used for recording channel activity.</p><p><b>RESULTS</b>(1) K(CA) from human mesenteric artery SMC was voltage dependent. Single channel conductance was 191.4 pS and 197.7 pS in EH group and normal group respectively. The channel activity was blocked by TEA in cytoplastic side. (2) With the increasing of Ca2+ concentration in the bath solution (fron 0 to 10(-8), 10(-7), 5 x 10(-7), 10(-6) mol/L), the K(Ca) channel open probability (Po) of two groups were increased, Po of EH group increased from 0.016 to 0.023, 0.031, 0.0153, 0.094, Po of normal group increased from 0.004 to 0.023, 0.041, 0.072, 0.184. The mean open time lengthened and the mean close time shortened. (3) Po of K(Ca) of EH group was higher than that of normal group when Ca2+ concentration was 0, but it was equal with or lower than normal group at the other Ca2+ concentrations.</p><p><b>CONCLUSION</b>K(Ca) of mesenteric artery SMC from EH group has a lower Ca2+ sensitivity than that of normal person. This might be an active factor for the onset of EH.</p>

Regulation of calcium-activated potassium channels of mesenteric artery smooth muscle from patients with essential hypertension by endothelin-1 and prostagl E1 / 中华心血管病杂志

<p><b>OBJECTIVE</b>To study regulation of Ca(2+)-activated K(+) channels (KCa) of mesenteric artery smooth muscle cell (SMC) from 21 old patients with essential hypertension (EH) by endothelin-1 (ET-1) and prostagl E(1) (PGE(1)).</p><p><b>METHODS</b>Mesenteric artery branch from EH was digested by enzyme. Patch clamp technique was used to pull cell-attached and inside-out patches on mesenteric artery SMC from EH and the normotensive patients respectively. The signal channel open probability (Po), open dwell-time (To) and close dwell-time (Tc), open channel number per patch were recorded. After adding Ca(2+) (10(-8) approximately 10(-6) mol/L), ET-1(2 approximately 8 x 10(9) mol/L) and PGE(1) (10, 20, 40, 100, 200, 400 nmol/L) to cytoplasm respectively. The parameters above were observed again.</p><p><b>RESULTS</b>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 it was few changes in EH group. KCa channels has dual reaction to ET-1 in normotensive patients. We have found no statistics difference when ET-1 present on KCa channels of EH cases. Whereas PGE(1) can affect KCa channels current and channels kinetic significantly in side-out patches. The Po of KCa channels increased. The To protracted and the Tc curtailed in EH.</p><p><b>CONCLUSIONS</b>The activities of KCa channels of patients with EH increased significantly. but the sensitive to Ca(2+) decreased. ET-1 were few effect to KCa channels. The PGE(1) can activated KCa channels of patients with EH.</p>