期刊
BRITISH JOURNAL OF PHARMACOLOGY
卷 179, 期 12, 页码 2953-2968出版社
WILEY
DOI: 10.1111/bph.15779
关键词
amitriptyline; ENaC; hypokalaemia; Kcnj10; Kcnj16; K-ir (IRK) channels
资金
- Department of Veteran Affairs [I01 BX004024]
- SC SmartState Centers of Excellence
- National Institutes of Health [R01/DK120821, R35/HL135749, R56 DK121750, RO1/DK126720, T32/HL134643, R35 HL135749, R01 DK126720, T32 HL134643, R01 DK120821]
- RSF Russian Science Foundation [19-14-00114]
- Russian Science Foundation [19-14-00114] Funding Source: Russian Science Foundation
The inhibition of K(ir)4.1/K(ir)5.1 channels affects ENaC activity, leading to the regulation of electrolyte balance and blood pressure. Amitriptyline is a potential K(ir)4.1/K(ir)5.1 inhibitor.
Background and Purpose Inwardly rectifying K+ (K-ir) channels located on the basolateral membrane of epithelial cells of the distal nephron play a crucial role in K+ handling and BP control, making these channels an attractive target for the treatment of hypertension. The purpose of the present study was to determine how the inhibition of basolateral K(ir)4.1/K(ir)5.1 heteromeric K+ channel affects epithelial sodium channel (ENaC)-mediated Na+ transport in the principal cells of cortical collecting duct (CCD). Experimental Approach The effect of fluoxetine, amitriptyline and recently developed K-ir inhibitor, VU0134992, on the activity of K(ir)4.1, K(ir)4.1/K(ir)5.1 and ENaC were tested using electrophysiological approaches in CHO cells transfected with respective channel subunits, cultured polarized epithelial mCCD(cl1) cells and freshly isolated rat and human CCD tubules. To test the effect of pharmacological K(ir)4.1/K(ir)5.1 inhibition on electrolyte homeostasis in vivo and corresponding changes in distal tubule transport, Dahl salt-sensitive rats were injected with amitriptyline (15 mg center dot kg(-1)center dot day(-1)) for 3 days. Key Results We found that inhibition of K(ir)4.1/K(ir)5.1, but not the K(ir)4.1 channel, depolarizes the cell membrane, induces the elevation of intracellular Ca2+ concentration and suppresses ENaC activity. Furthermore, we demonstrate that amitriptyline administration leads to a significant drop in plasma K+ level, triggering sodium excretion and diuresis. Conclusion and Implications The present data uncover a specific role of the K(ir)4.1/K(ir)5.1 channel in the modulation of ENaC activity and emphasize the potential for using K(ir)4.1/K(ir)5.1 inhibitors to regulate electrolyte homeostasis and BP.
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