Age-related decreases in endocochlear potential are associated with vascular abnormalities in the stria vascularis

1996 ◽  
Vol 102 (1-2) ◽  
pp. 181-190 ◽  
Author(s):  
M.A. Gratton ◽  
R.A. Schmiedt ◽  
B.A. Schulte
Pharmaceutics ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1041
Author(s):  
Jacqueline Chester ◽  
Edan Johnston ◽  
Daniel Walker ◽  
Melissa Jones ◽  
Corina Mihaela Ionescu ◽  
...  

Aging is considered a contributing factor to many diseases such as cardiovascular disease, Alzheimer’s disease, and hearing loss. Age-related hearing loss, also termed presbycusis, is one of the most common sensory impairments worldwide, affecting one in five people over 50 years of age, and this prevalence is growing annually. Associations have emerged between presbycusis and detrimental health outcomes, including social isolation and mental health. It remains largely untreatable apart from hearing aids, and with no globally established prevention strategies in the clinical setting. Hence, this review aims to explore the pathophysiology of presbycusis and potential therapies, based on a recent advancement in bile acid-based bio-nanotechnologies. A comprehensive online search was carried out using the following keywords: presbycusis, drugs, hearing loss, bile acids, nanotechnology, and more than 150 publications were considered directly relevant. Evidence of the multifaceted oxidative stress and chronic inflammation involvement in cellular damage and apoptosis that is associated with a loss of hair cells, damaged and inflamed stria vascularis, and neuronal signalling loss and apoptosis continues to emerge. New robust and effective therapies require drug delivery deeper into the various layers of the cochlea. Bile acid-based nanotechnology has gained wide interest in its permeation-enhancing ability and potential for numerous applications in treating presbycusis.


2002 ◽  
Vol 282 (2) ◽  
pp. C403-C407 ◽  
Author(s):  
Daniel C. Marcus ◽  
Tao Wu ◽  
Philine Wangemann ◽  
Paulo Kofuji

Stria vascularis of the cochlea generates the endocochlear potential and secretes K+. K+ is the main charge carrier and the endocochlear potential the main driving force for the sensory transduction that leads to hearing. Stria vascularis consists of two barriers, marginal cells that secrete potassium and basal cells that are coupled via gap junctions to intermediate cells. Mice lacking the KCNJ10 (Kir4.1) K+ channel in strial intermediate cells did not generate an endocochlear potential. Endolymph volume and K+ concentration ([K+]) were reduced. These studies establish that the KCNJ10 K+ channel provides the molecular mechanism for generation of the endocochlear potential in concert with other transport pathways that establish the [K+] difference across the channel. KCNJ10 is also a limiting pathway for K+ secretion.


2017 ◽  
Vol 29 (3) ◽  
pp. 585 ◽  
Author(s):  
Weiwei Guo ◽  
Haijin Yi ◽  
Zhang Yan ◽  
Lili Ren ◽  
Lei Chen ◽  
...  

The purpose of this study was to examine the morphological and functional development of the lateral wall of the scala media of the cochlea in miniature pigs; light and transmission electron microscopy and electrophysiology were used for this purpose. We showed that the lateral wall of the scala media of the cochlea appears at embryonic Day 21 (E21) when the cochlear duct begins to form. From E28 to E49, the lateral wall can be distinguished according to its position along the cochlea. At E56, cells in the lateral wall begin to differentiate into three different types. At E70, three cell types, marginal, intermediate and basal, can be clearly distinguished. At E91, the stria vascularis is adult-like and the organ of Corti is also morphologically mature. The average endocochlear potential measured from the second turn of the cochlea (at E98, postnatal Day 1 (P1), P13 and P30) was 71.4 ± 2.5 (n = 7), 78.8 ± 1.5 (n = 10), 77.3 ± 2.3 (n = 10) and 78.0 ± 2.1 mV (n = 10), respectively. Our results suggest that in miniature pigs the stria vascularis develops during the embryonic period, concurrent with maturation of the organ of Corti. The magnitude of the endocochlear potential reached its mature level when the stria vascularis was morphologically adult-like at E98. These findings provide a morphological and functional basis for future animal studies using the miniature pig model concerning the pathogenesis of various inner-ear diseases.


1987 ◽  
Vol 29 (2-3) ◽  
pp. 117-124 ◽  
Author(s):  
Franklin F. Offner ◽  
Peter Dallos ◽  
Mary Ann Cheatham

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