scholarly journals Kir4.1/Kir5.1 in the DCT plays a role in the regulation of renal K+ excretion

2019 ◽  
Vol 316 (3) ◽  
pp. F582-F586 ◽  
Author(s):  
Xiao-Tong Su ◽  
David H. Ellison ◽  
Wen-Hui Wang
Keyword(s):  
Angiotensin Ii ◽  
Potassium Channel ◽  
Metabolic Alkalosis ◽  
Potassium Conductance ◽  
Thick Ascending Limb ◽  
Potassium Intake ◽  
Inwardly Rectifying Potassium Channel ◽  
Inwardly Rectifying

The aim of this mini review is to provide an overview regarding the role of inwardly rectifying potassium channel 4.1 (Kir4.1)/Kir5.1 in regulating renal K+ excretion. Deletion of Kir4.1 in the kidney inhibited thiazide-sensitive NaCl cotransporter (NCC) activity in the distal convoluted tubule (DCT) and slightly suppressed Na-K-2Cl cotransporter (NKCC2) function in the thick ascending limb (TAL). Moreover, increased dietary K+ intake inhibited, whereas decreased dietary K+ intake stimulated, the basolateral potassium channel (a Kir4.1/Kir5.1 heterotetramer) in the DCT. The alteration of basolateral potassium conductance is essential for the effect of dietary K+ intake on NCC because deletion of Kir4.1 in the DCT abolished the effect of dietary K+ intake on NCC. Since potassium intake-mediated regulation of NCC plays a key role in regulating renal K+ excretion and potassium homeostasis, the deletion of Kir4.1 caused severe hypokalemia and metabolic alkalosis under control conditions and even during increased dietary K+ intake. Finally, recent studies have suggested that the angiotensin II type 2 receptor (AT2R) and bradykinin-B2 receptor (BK2R) are involved in mediating the effect of high dietary K+ intake on Kir4.1/Kir5.1 in the DCT.

scholarly journals Unconventional Role of the Inwardly Rectifying Potassium Channel Kir2.2 as a Constitutive Activator of RelA in Cancer

2012 ◽  
Vol 73 (3) ◽  
pp. 1056-1062 ◽  
Author(s):  
Inkyoung Lee ◽  
Sook-Ja Lee ◽  
Tong Mook Kang ◽  
Won Ki Kang ◽  
Chaehwa Park
Keyword(s):  
Potassium Channel ◽  
Inwardly Rectifying Potassium Channel ◽  
Inwardly Rectifying

scholarly journals Cell-type-specific regulation of neuronal intrinsic excitability by macroautophagy

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Ori J Lieberman ◽  
Micah D Frier ◽  
Avery F McGuirt ◽  
Christopher J Griffey ◽  
Elizabeth Rafikian ◽  
...  
Keyword(s):  
Potassium Channel ◽  
Dendritic Structure ◽  
Intrinsic Excitability ◽  
Projection Neurons ◽  
Inwardly Rectifying Potassium Channel ◽  
Cell Type Specific ◽  
Subcortical Nuclei ◽  
Specific Regulation ◽  
Inwardly Rectifying

The basal ganglia are a group of subcortical nuclei that contribute to action selection and reinforcement learning. The principal neurons of the striatum, spiny projection neurons of the direct (dSPN) and indirect (iSPN) pathways, maintain low intrinsic excitability, requiring convergent excitatory inputs to fire. Here, we examined the role of autophagy in mouse SPN physiology and animal behavior by generating conditional knockouts of Atg7 in either dSPNs or iSPNs. Loss of autophagy in either SPN population led to changes in motor learning but distinct effects on cellular physiology. dSPNs, but not iSPNs, required autophagy for normal dendritic structure and synaptic input. In contrast, iSPNs, but not dSPNs, were intrinsically hyperexcitable due to reduced function of the inwardly rectifying potassium channel, Kir2. These findings define a novel mechanism by which autophagy regulates neuronal activity: control of intrinsic excitability via the regulation of potassium channel function.

Anti-Hypertensive Potential and Epigenetics of Angiotensin II type 2 Receptor (AT2R)

2020 ◽  
Vol 16 ◽  
Author(s):  
Mayank Chaudhary
Keyword(s):  
Blood Pressure ◽  
Angiotensin Ii ◽  
Renin Angiotensin System ◽  
Blood Pressure Regulation ◽  
Biologically Active ◽  
Pressure Regulation ◽  
Tissue Remodelling ◽  
Critical Pathway

Background:: Renin angiotensin system (RAS) is a critical pathway involved in blood pressure regulation. Octapeptide, angiotensin II (Ang aII), is biologically active compound of RAS pathway which mediates its action by binding to either angiotensin II type 1 receptor (AT1R) or angiotensin II type 2 receptor (AT2R). Binding of Ang II to AT1R facilitates blood pressure regulation whereas AT2R is primarily involved in wound healing and tissue remodelling. Objective:: Recent studies have highlighted additional role of AT2R to counter balance detrimental effects of AT1R. Activation of angiotensin II type 2 receptor using AT2R agonist has shown effect on natriuresis and release of nitric oxide. Additionally, AT2R activation has been found to inhibit angiotensin converting enzyme (ACE) and enhance angiotensin receptor blocker (ARB) activity. These findings highlight the potential of AT2R as novel therapeutic target against hypertension. Conclusion:: The potential role of AT2R highlights the importance of exploring additional mechanisms that might be crucial for AT2R expression. Epigenetic mechanisms including DNA methylation and histone modification have been explored vastly with relation to cancer but role of such mechanisms on expression of AT2R has recently gained interest.

The inwardly rectifying potassium channel subunit Kir2.2v (KCNJN1) maps to 17p11.2→p11.1

1997 ◽  
Vol 79 (1-2) ◽  
pp. 85-87 ◽  
Author(s):  
N. Namba ◽  
R. Mori ◽  
H. Tanaka ◽  
I. Kondo ◽  
K. Narahara ◽  
...  
Keyword(s):  
Potassium Channel ◽  
Inwardly Rectifying Potassium Channel ◽  
Inwardly Rectifying

Abstract 7: Angiotensin II Type 2 Receptor Deficiency Increases Renal ACE/ACE2 Ratio-Ang II-AT1R Expression In Male but not in Female Mice

Hypertension ◽  
2012 ◽  
Vol 60 (suppl_1) ◽  
Author(s):  
Quaisar Ali ◽  
Yonnie Wu ◽  
Tadashi Inagami ◽  
Tahir Hussain
Keyword(s):  
Blood Pressure ◽  
Renal Function ◽  
Angiotensin Ii ◽  
Renin Activity ◽  
Ang Ii ◽  
Male And Female ◽  
Female Mice ◽  
Gender Specific

Angiotensin II acting via Angiotensin II type 2 receptors (AT2Rs) is believed to be protective against blood pressure increase and affects renal function under pathophysiological condition. Recently we have observed that stimulation of AT2Rs in male obese Zucker rats has shifted the two opposing arms of renin angiotensin system (RAS) i.e. ACE-Ang II-AT1 vs ACE2/Ang-(1-7)-Mas. Evidence suggests that estrogen regulates RAS, including AT2R in female mice. We hypothesized that AT2R has a gender specific regulation of RAS. In the present study, we investigated the role of AT2Rs in regulating RAS components in male and female mice. Kidney cortex from AT2R knockout (AT2RKO) male and female mice and wild type (WT) with similar background (C57BL/6) of 20 weeks of age were used in the study. The cortical ACE expression (ng ACE/μg tissue) was significantly increased in AT2RKO mice (3±0.02) compared to WT males (1.9±0.02). LC/MS analysis of cortical tissue revealed that Ang II was also significantly increased in AT2RKO mice (WT: 31±3, AT2RKO: 47±3 fmoles/mg tissue). Deletion of AT2R significantly increased AT1R (204%, 204 of 100) expression and had no effect on renin activity compared to WT males. The cortical expression of ACE2 activity (WT: 113±8, AT2RKO: 40±11, RFU/min), Ang-(1-7) levels (WT: 7.3±1.4, AT2RKO: 3±0.8 fmoles/mg tissue) and Mas receptor (AT2RKO: 54±15, % of WT) was significantly decreased in AT2RKO males compared to WT. The cortical expression of the AT2R and MasR was 2-fold greater in WT females compared to WT male. The renin activity (WT: 32±2, AT2RKO: 21±0.3, RFU/min) and MasR expression (WT: 187.5±55, AT2KO: 47±9) was significantly decreased in AT2RKO females compared to the female WT. Interestingly, Ang-(1-7) level (WT: 5.7±0.7, AT2RKO 2.6±0.7 fmoles/mg tissue) was decreased but no changes in ACE or ACE2 activity was observed in AT2KO females compared to their WT, suggesting a role of non-ACE2 pathway. This study suggests that AT2R regulates ACE/ACE2 ratio-Ang II-AT1R expression negatively only in males, whereas in females, it regulates Ang-(1-7) potentially via non-ACE2 pathway. Such changes indicate a gender specific mechanisms potentially associated with AT2R-mediated regulation of renal function and blood pressure control.

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