Action potential-like responses due to the inward rectifying potassium channel

1986 ◽  
Vol 90 (2) ◽  
pp. 115-122 ◽  
Author(s):  
Yves Tourneur
Keyword(s):  
Action Potential ◽  
Potassium Channel ◽  
Inward Rectifying Potassium Channel

scholarly journals A Weakly Inward Rectifying Potassium Channel of the Salmon Brain

1996 ◽  
Vol 271 (26) ◽  
pp. 15729-15735 ◽  
Author(s):  
Yoshihiro Kubo ◽  
Tomoyuki Miyashita ◽  
Kaoru Kubokawa
Keyword(s):  
Potassium Channel ◽  
Weakly Inward ◽  
Inward Rectifying Potassium Channel

scholarly journals Comparative gain-of-function effects of the KCNMA1-N999S mutation on human BK channel properties

2020 ◽  
Vol 123 (2) ◽  
pp. 560-570 ◽  
Author(s):  
Hans J. Moldenhauer ◽  
Katia K. Matychak ◽  
Andrea L. Meredith
Keyword(s):  
Action Potential ◽  
Potassium Channel ◽  
Antiepileptic Drug ◽  
Bk Channel ◽  
Gain Of Function ◽  
Double Mutation ◽  
Brain Physiology ◽  
Number Of Patients ◽  
Calcium Activated Potassium Channel ◽  
Channel Properties

KCNMA1, encoding the voltage- and calcium-activated potassium channel, has a pivotal role in brain physiology. Mutations in KCNMA1 are associated with epilepsy and/or dyskinesia (PNKD3). Two KCNMA1 mutations correlated with these phenotypes, D434G and N999S, were previously identified as producing gain-of-function (GOF) effects on BK channel activity. Three new patients have been reported harboring N999S, one carrying a second mutation, R1128W, but the effects of these mutations have not yet been reported under physiological K+ conditions or compared to D434G. In this study, we characterize N999S, the novel N999S/R1128W double mutation, and D434G in a brain BK channel splice variant, comparing the effects on BK current properties under a physiological K+ gradient with action potential voltage commands. N999S, N999S/R1128W, and D434G cDNAs were expressed in HEK293T cells and characterized by patch-clamp electrophysiology. N999S BK currents were shifted to negative potentials, with faster activation and slower deactivation compared with wild type (WT) and D434G. The double mutation N999S/R1128W did not show any additional changes in current properties compared with N999S alone. The antiepileptic drug acetazolamide was assessed for its ability to directly modulate WT and N999S channels. Neither the WT nor N999S channels were sensitive to the antiepileptic drug acetazolamide, but both were sensitive to the inhibitor paxilline. We conclude that N999S is a strong GOF mutation that surpasses the D434G phenotype, without mitigation by R1128W. Acetazolamide has no direct modulatory action on either WT or N999S channels, indicating that its use may not be contraindicated in patients harboring GOF KCNMA1 mutations. NEW & NOTEWORTHY KCNMA1-linked channelopathy is a new neurological disorder characterized by mutations in the BK voltage- and calcium-activated potassium channel. The epilepsy- and dyskinesia-associated gain-of-function mutations N999S and D434G comprise the largest number of patients in the cohort. This study provides the first direct comparison between D434G and N999S BK channel properties as well as a novel double mutation, N999S/R1128W, from another patient, defining the functional effects during an action potential stimulus.

scholarly journals Loss of ATP-Sensitive Potassium Channel Surface Expression in Heart Failure Underlies Dysregulation of Action Potential Duration and Myocardial Vulnerability to Injury

PLoS ONE ◽  
2016 ◽  
Vol 11 (3) ◽  
pp. e0151337 ◽  
Author(s):  
Zhan Gao ◽  
Ana Sierra ◽  
Zhiyong Zhu ◽  
Siva Rama Krishna Koganti ◽  
Ekaterina Subbotina ◽  
...  
Keyword(s):  
Heart Failure ◽  
Action Potential ◽  
Potassium Channel ◽  
Action Potential Duration ◽  
Surface Expression ◽  
Channel Surface

The predisposition to thyrotoxic periodic paralysis (TPP) is due to a genetic variant in the inward-rectifying potassium channel,KCNJ2

2013 ◽  
Vol 80 (5) ◽  
pp. 770-771 ◽  
Author(s):  
Xingyan Wang ◽  
Chun Chung Chow ◽  
Xiaoqiang Yao ◽  
Gary T. C. Ko ◽  
Clive S. Cockram ◽  
...  
Keyword(s):  
Potassium Channel ◽  
Genetic Variant ◽  
Periodic Paralysis ◽  
Thyrotoxic Periodic Paralysis ◽  
Inward Rectifying Potassium Channel

Lack of confirmation of anti-inward rectifying potassium channel 4.1 antibodies as reliable markers of multiple sclerosis

2014 ◽  
Vol 20 (13) ◽  
pp. 1699-1703 ◽  
Author(s):  
Elodie Nerrant ◽  
Céline Salsac ◽  
Mahmoud Charif ◽  
Xavier Ayrignac ◽  
Clarisse Carra-Dalliere ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Potassium Channel ◽  
Immunosorbent Assay ◽  
Neurological Diseases ◽  
Enzyme Linked Immunosorbent Assay ◽  
Healthy Controls ◽  
Lower Prevalence ◽  
Immunofluorescence Analysis ◽  
Specific Staining ◽  
Inward Rectifying Potassium Channel

Background: auto-antibodies against the potassium channel inward rectifying potassium channel 4.1 (Kir4.1) have previously been identified in 46% of patients with multiple sclerosis (MS). Objectives: to confirm these findings. Methods: we evaluated the presence of anti-Kir4.1 antibodies by enzyme-linked immunosorbent assay (ELISA) and immunofluorescence in 268 MS patients, 46 patients with other neurological diseases (OND) and 45 healthy controls. Results: anti-Kir4.1 antibodies were found in 7.5% of MS patients, 4.3% of OND patients and 4.4% of healthy controls. Immunofluorescence analysis did not identify any specific staining. Conclusions: we confirmed the presence of anti-Kir4.1 antibodies in MS patients, but at a much lower prevalence than previously reported.

scholarly journals Engineering prokaryotic channels for control of mammalian tissue excitability

2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Hung X. Nguyen ◽  
Robert D. Kirkton ◽  
Nenad Bursac
Keyword(s):  
Action Potential ◽  
Sodium Channels ◽  
Connexin 43 ◽  
De Novo ◽  
Interstitial Fibrosis ◽  
Human Fibroblasts ◽  
Mammalian Tissue ◽  
Voltage Gated Sodium Channels ◽  
Inward Rectifying Potassium Channel

Abstract The ability to directly enhance electrical excitability of human cells is hampered by the lack of methods to efficiently overexpress large mammalian voltage-gated sodium channels (VGSC). Here we describe the use of small prokaryotic sodium channels (BacNav) to create de novo excitable human tissues and augment impaired action potential conduction in vitro. Lentiviral co-expression of specific BacNav orthologues, an inward-rectifying potassium channel, and connexin-43 in primary human fibroblasts from the heart, skin or brain yields actively conducting cells with customizable electrophysiological phenotypes. Engineered fibroblasts (‘E-Fibs’) retain stable functional properties following extensive subculture or differentiation into myofibroblasts and rescue conduction slowing in an in vitro model of cardiac interstitial fibrosis. Co-expression of engineered BacNav with endogenous mammalian VGSCs enhances action potential conduction and prevents conduction failure during depolarization by elevated extracellular K+, decoupling or ischaemia. These studies establish the utility of engineered BacNav channels for induction, control and recovery of mammalian tissue excitability.

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