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健康科學學院 > 醫學研究所 > 期刊論文 >

題名:Midazolam’s Effects on Delayed-Rectifier K+ Current and Intermediate-Conductance Ca2+-Activated K+ Channel in Jurkat T-lymphocytes
作者:Ning-Ping Foo , Yu-Fan Liu , Ping-Ching Wu , Chung-Hsi Hsing , Bu-Miin Huang , and Edmund-Cheung So
期刊名稱:International Journal of Molecular Sciences
摘要:: Midazolam (MDZ) could affect lymphocyte immune functions. However, the influence of MDZ on cell’s K+ currents has never been investigated. Thus, in the present study, the effects of MDZ on Jurkat T lymphocytes were studied using the patch-clamp technique. Results showed that MDZ suppressed the amplitude of delayed-rectifier K+ current (IK(DR)) in concentration-, time-, and statedependent manners. The IC50 for MDZ-mediated reduction of IK(DR) density was 5.87 µM. Increasing MDZ concentration raised the rate of current-density inactivation and its inhibitory action on IK(DR) density was estimated with a dissociation constant of 5.14 µM. In addition, the inactivation curve of IK(DR) associated with MDZ was shifted to a hyperpolarized potential with no change on the slope factor. MDZ-induced inhibition of IK(DR) was not reversed by flumazenil. In addition, the activity of intermediate-conductance Ca2+-activated K+ (IKCa) channels was suppressed by MDZ. Furthermore, inhibition by MDZ on both IK(DR) and IKCa-channel activity appeared to be independent from GABAA receptors and affected immune-regulating cytokine expression in LPS/PMA-treated human T lymphocytes. In conclusion, MDZ suppressed current density of IK(DR) in concentration-, time-, and state-dependent manners in Jurkat T-lymphocytes and affected immune-regulating cytokine expression in LPS/PMA-treated human T lymphocytes.
英文關鍵字:lymphocyte; delayed-rectifier K+ current; inactivation kinetics; midazolam; interleukin; intermediate conductance Ca2+-activated K+ channel; interleukin