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Basic psychopharmacology
Published in Jonathan P Rogers, Cheryl CY Leung, Timothy RJ Nicholson, Pocket Prescriber Psychiatry, 2019
Jonathan P Rogers, Cheryl CY Leung, Timothy RJ Nicholson
Drugs can block these ion channels. For example lamotrigine and carbamazepine bind voltage-gated sodium channels and stabilise them in the inactive state; gabapentin and pregabalin bind to the presynaptic voltage-gated potassium channel, reducing release of neurotransmitters.
The cardiac myocyte: excitation and contraction
Published in Neil Herring, David J. Paterson, Levick's Introduction to Cardiovascular Physiology, 2018
Neil Herring, David J. Paterson
This has a similar structure to KS but it is composed of differ-ent proteins, voltage-gated potassium channel subunit Kv4.3 (KCND3) and Kv channel-interacting protein 2 (KCIP2). It has a faster activation and inactivation than KS. KCND3 expres-sion is reduced in failing hearts, leading to prolonged action potentials.
Laboratory Diagnosis of CNS Viral Infections
Published in Sunit K. Singh, Daniel Růžek, Neuroviral Infections, 2013
Alexander C. Outhred, Jen Kok, Dominic E. Dwyer
Anti-voltage-gated potassium channel (VGKC) antibodies can present as a limbic encephalitis, although most cases have a more gradual onset that can instead lead to misdiagnosis as a degenerative or prion disease (Tan et al. 2008). Like anti-NMDA-receptor encephalitis, the majority of cases are associated with an underlying neoplastic process and manifestations are reversible after tumor removal and immunotherapy to reduce anti-VGKC antibodies.
Why do platelets express K+ channels?
Published in Platelets, 2021
Joy R Wright, Martyn P. Mahaut-Smith
Transcripts were also detected in platelets for several β-subunits that modulate the pore-forming α-subunits of voltage-gated potassium channels, including the voltage-gated Shaker-related subunits (KCNAB1,2, and 3). KCNAB1 has been reported to modulate the channel activity of voltage-gated potassium α-subunits, promoting its expression at the cell membrane, but also accelerating the channel pore closure [70,71], possibly through the binding of NADPH [72]. KCNE3 (MiRP2) from the Isk-related family is another β-subunit that has been reported to form complexes with the α-subunits of voltage-gated potassium channels, resulting in reduced current density and modulation of channel activation rates [73]. Another KCNE subunit (KCNE4, MiRP3) has been reported to retain Kv1.3 in the endoplasmic reticulum of leukocytes when the surface targeting motif of Kv1.3 COOH terminus is masked [74], and KCNRG (Potassium Channel Regulatory Protein) encodes a soluble protein that has been suggested interferes with the assembly of Kv channels, suppressing K+ currents [75,76]. Therefore, several candidates exist for β-subunits with regulatory roles in platelet K+ channel function that are worthwhile exploring in future studies.
Potassium channels as prominent targets and tools for the treatment of epilepsy
Published in Expert Opinion on Therapeutic Targets, 2021
The relationship between mutations in other voltage-gated potassium channels with human epilepsy is less clear. Pathogenic variants of Kv channels (including de novo) were found mostly in patients with rare forms of epilepsy, including epileptic encephalopathies (Kv1.1, Kv1.2, Kv 2.1, Kv3.2, Kv8.2) [62–71], myoclonus epilepsy and ataxia (Kv3.1) [72–75], a genetic form of temporal lobe epilepsy (TLE) (Kv4.2, Kv1.3) [76,77], episodic ataxia with generalized/focal seizures (Kv1.1, Kv1.2) [78,79], Temple-Baraitser syndrome with epilepsy (Kv10.1) [80], febrile and afebrile focal seizures (Kv8.2) [71], epilepsy with centrotemporal spikes [81]. Epilepsy with generalized and focal seizures is a key phenotypic feature in most individuals with KCNH1-related syndromes [82,83]. Mutations of Kv4.2 channels were found in patients with epilepsy-autism comorbidity [84]. Pathogenic variants of the KCNH2 gene encoding the pore-forming subunit of Kv11.1 channel have been identified in patients with inherited cardiac problems and epilepsy [85–87].
Mechano-gated channels in C. elegans
Published in Journal of Neurogenetics, 2020
Evolutionary genetics revealed that potassium channels are widely expressed archaic ion channels across species. Potassium channels control the influx and efflux of K+ ions through cell membranes (Douguet & Honore, 2019). The opposing polarization and depolarization of potassium versus calcium and sodium channels promote membrane potential/cell excitability for numerous vital cellular mechanics as well as survival. To date, four main classes of potassium channels are known—Calcium-activated (Kca), Inward rectifying (Kir), Tandem/two pore domain (K2P) and voltage-gated potassium channels (KV). Previously known as K+ background (leak) channels, K2P channel subunits are encoded by 15 KCNK mammalian genes, 11 Drosophila genes and 50 putative C. elegans genes. Out of the four potassium ion channels, only two K2P subfamilies—Tandem pore domain in weak rectifying K+ channel (TWIK) and TWIK-related K+ channel (TREK) have been divulged as mechano-gated channels. Thus far, TREK1 (KCNK2), TREK2 (KCNK10) and TRAAK (TWIK-related arachidonic acid-stimulated K+) channels have been found to be mechano-gated channels in mammals (Chalfie, 2009) but there is yet no mechanically activated K2P channel exposed in C. elegans.