The role of an inwardly rectifying K+ channel (Kir4.1) in the inner ear and hearing loss

There is growing otologic interest in treating inner ear disorders, such as sudden sensorineural hearing loss and acute or unremitting Meniere's disease, with intratympanic dexamethasone (IT-DEX). Although anecdotally reported, there are no scientific clinical papers and few prior laboratory research publications on the subject. This study compares perilymph dexamethasone concentrations after systemic and intratympanic administration and assesses the role of 3 potential transport facilitators of IT-DEX into perilymph. Forty guinea pigs (79 ears) were randomly separated into 5 groups. Dexamethasone levels were measured by radioimmunoassay. IT-DEX resulted in higher perilymph steroid levels than intravenous dexamethasone ( P < 0.05). Histamine facilitator resulted in significantly higher perilymph steroid levels than IT-DEX alone ( P < 0.05). Neither hyaluronic acid nor dimethylsulfoxide was a potent facilitator. This study demonstrates that IT-DEX administration results in superior perilymph levels within 1 hour of administration and does not result in systemic absorption. Histamine is a potent facilitating agent. The clinical implications are considerable.

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The Role of Pseudoephedrine Tablets Versus Xylometazoline Spray in Otic Barotrauma Prevention During Flights

Revista de Chimie ◽

10.37358/rc.18.11.6711 ◽

2018 ◽

Vol 69 (11) ◽

pp. 3199-3202

Author(s):

Ruxandra Oana Iana ◽

Dragos Cristian Stefanescu ◽

Viorel Zainea ◽

Razvan Hainarosie

Keyword(s):

Hearing Loss ◽

Inner Ear ◽

Tympanic Membrane ◽

Eustachian Tube ◽

Middle Ear ◽

Severe Pain ◽

Air Pressure ◽

Membrane Rupture ◽

Common Complaint

Otalgia during airplane flights is a common complaint among patients. This occurs due to the changes in air pressure during take-off and landing that affect middle ear and inner ear. The eustachian tube is responsible with equalizing pressure but in many cases, it happens insufficiently leading to mild to severe pain, hearing loss, tympanic membrane rupture and even inner ear lesions. The aim of this paper is to asses the efficacy of two decongestants, oral pseudoephedrine versus topical xylometazoline in preventing otic barotrauma.

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The Role of FoxG1 in the Inner Ear

Frontiers in Cell and Developmental Biology ◽

10.3389/fcell.2020.614954 ◽

2020 ◽

Vol 8 ◽

Author(s):

Yanyan Ding ◽

Wei Meng ◽

Weijia Kong ◽

Zuhong He ◽

Renjie Chai

Keyword(s):

Hearing Loss ◽

Inner Ear ◽

Signal Transmission ◽

Sensorineural Deafness ◽

Auditory Signal ◽

Forkhead Box ◽

Inner Ear Development ◽

Ototoxic Drugs ◽

And Function

Sensorineural deafness is mainly caused by damage to the tissues of the inner ear, and hearing impairment has become an increasingly serious global health problem. When the inner ear is abnormally developed or is damaged by inflammation, ototoxic drugs, or blood supply disorders, auditory signal transmission is inhibited resulting in hearing loss. Forkhead box G1 (FoxG1) is an important nuclear transcriptional regulator, which is related to the differentiation, proliferation, development, and survival of cells in the brain, telencephalon, inner ear, and other tissues. Previous studies have shown that when FoxG1 is abnormally expressed, the development and function of inner ear hair cells is impaired. This review discusses the role and regulatory mechanism of FoxG1 in inner ear tissue from various aspects – such as the effect on inner ear development, the maintenance of inner ear structure and function, and its role in the inner ear when subjected to various stimulations or injuries – in order to explain the potential significance of FoxG1 as a new target for the treatment of hearing loss.

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Erratum to: Role of Calcineurin-Mediated Dephosphorylation in Modulation of an Inwardly Rectifying K+ Channel in Human Proximal Tubule Cells

The Journal of Membrane Biology ◽

10.1007/s00232-009-9220-2 ◽

2009 ◽

Vol 233 (1-3) ◽

pp. 143-143

Author(s):

Manabu Kubokawa ◽

Toshiyuki Kojo ◽

You Komagiri ◽

Kazuyoshi Nakamura

Keyword(s):

Proximal Tubule ◽

K Channel ◽

Proximal Tubule Cells ◽

Tubule Cells ◽

Inwardly Rectifying ◽

Human Proximal Tubule

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Autism with Seizures and Intellectual Disability: Possible Causative Role of Gain-of-function of the Inwardly-Rectifying K+ Channel Kir4.1

Neurobiology of Disease ◽

10.1016/j.nbd.2011.03.016 ◽

2011 ◽

Vol 43 (1) ◽

pp. 239-247 ◽

Cited By ~ 72

Author(s):

Federico Sicca ◽

Paola Imbrici ◽

Maria Cristina D'Adamo ◽

Francesca Moro ◽

Fabrizia Bonatti ◽

...

Keyword(s):

Intellectual Disability ◽

K Channel ◽

Causative Role ◽

Gain Of Function ◽

Inwardly Rectifying

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EXPRESSION AND SPECIFIC SUBCELLULAR LOCALIZATION OF AN INWARDLY RECTIFYING K+ CHANNEL, KIR4.1/KAB-2, IN THE RAT INNER EAR

Recent Developments in Auditory Mechanics ◽

10.1142/9789812793980_0013 ◽

2000 ◽

Author(s):

H. HIBINO ◽

K. DOI ◽

T. KUBO ◽

T. GOTOW ◽

Y. UCHIYAMA ◽

...

Keyword(s):

Subcellular Localization ◽

Inner Ear ◽

K Channel ◽

Inwardly Rectifying

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Immunoreactivity of Muscarinic Acetylcholine M2 and Serotonin 5-HT2B Receptors, Norepinephrine Transporter and Kir Channels in a Model of Epilepsy

Life ◽

10.3390/life11040276 ◽

2021 ◽

Vol 11 (4) ◽

pp. 276

Author(s):

Enes Akyuz ◽

Zuleyha Doganyigit ◽

Yam Nath Paudel ◽

Betul Koklu ◽

Emin Kaymak ◽

...

Keyword(s):

K Channel ◽

Neurotransmitter Receptors ◽

Extracellular Potassium ◽

Unexpected Death ◽

Kir Channels ◽

Ptz Kindling ◽

Neurotransmitter Activity ◽

K Concentration ◽

Inwardly Rectifying

Epilepsy is characterized by an imbalance in neurotransmitter activity; an increased excitatory to an inhibitory activity. Acetylcholine (ACh), serotonin, and norepinephrine (NE) may modulate neural activity via several mechanisms, mainly through its receptors/transporter activity and alterations in the extracellular potassium (K+) concentration via K+ ion channels. Seizures may disrupt the regulation of inwardly rectifying K+ (Kir) channels and alter the receptor/transporter activity. However, there are limited data present on the immunoreactivity pattern of these neurotransmitter receptors/transporters and K+ channels in chronic models of epilepsy, which therefore was the aim of this study. Changes in the immunoreactivity of epileptogenesis-related neurotransmitter receptors/transporters (M2, 5-HT2B, and NE transporter) as well as Kir channels (Kir3.1 and Kir6.2) were determined in the cortex, hippocampus and medulla of adult Wistar rats by utilizing a Pentylenetetrazol (PTZ)-kindling chronic epilepsy model. Increased immunoreactivity of the NE transporter, M2, and 5-HT2B receptors was witnessed in the cortex and medulla. While the immunoreactivity of the 5-HT2B receptor was found increased in the cortex and medulla, it was decreased in the hippocampus, with no changes observed in the M2 receptor in this region. Kir3.1 and Kir6.2 staining showed increase immunoreactivity in the cerebral cortex, but channel contrasting findings in the hippocampus and medulla. Our results suggest that seizure kindling may result in significant changes in the neurotransmitter system which may contribute or propagate to future epileptogenesis, brain damage and potentially towards sudden unexpected death in epilepsy (SUDEP). Further studies on the pathogenic role of these changes in neurotransmitter receptors/transporters and K+ channel immunoreactivity may identify newer possible targets to treat seizures or prevent epilepsy-related comorbidities.

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