Attenuation of noise-induced hyperactivity in the dorsal cochlear nucleus by pre-treatment with MK-801.

Autor: Criddle MW; Department of Otolaryngology, Wayne State University, Detroit, MI 48201, USA., Godfrey DA; Department of Neurology and Division of Otolaryngology and Dentistry, Department of Surgery, University of Toledo College of Medicine and Life Sciences, Toledo, OH 43610, USA., Kaltenbach JA; Department of Neurosciences, The Cleveland Clinic, Cleveland, OH 44195, USA. Electronic address: kaltenj@ccf.org.
Jazyk: angličtina
Zdroj: Brain research [Brain Res] 2018 Mar 01; Vol. 1682, pp. 71-77. Date of Electronic Publication: 2018 Jan 09.
DOI: 10.1016/j.brainres.2018.01.002
Abstrakt: It has previously been hypothesized that hyperactivity of central auditory neurons following exposure to intense noise is a consequence of synaptic alterations. Recent studies suggest the involvement of NMDA receptors in the induction of this hyperactive state. NMDA receptors can mediate long term changes in the excitability of neurons through their involvement in excitotoxic injury and long term potentiation and depression. In this study, we examined the effect of administering an NMDA receptor blocker on the induction of hyperactivity in the dorsal cochlear nucleus (DCN) following intense sound exposure. Our prediction was that if hyperactivity induced by intense sound exposure is dependent on NMDA receptors, then blocking these receptors by administering an NMDA receptor antagonist just before animals are exposed to intense sound should reduce the degree of hyperactivity that subsequently emerges. We compared the levels of hyperactivity that develop in the DCN after intense sound exposure to activity recorded in control animals that were not sound exposed. One group of animals to be sound exposed received intraperitoneal injection of MK-801 twenty minutes preceding the sound exposure, while the other group received injection of saline. Recordings performed in the DCN 26-28 days post-exposure revealed increased response thresholds and widespread increases in spontaneous activity in the saline-treated animals that had been sound exposed, consistent with earlier studies. The animals treated with MK-801 preceding sound exposure showed similarly elevated thresholds but an attenuation of hyperactivity in the DCN; the attenuation was most robust in the high frequency half of the DCN, but lower levels of hyperactivity were also found in the low frequency half. These findings suggest that NMDA receptors are an important component of the hyperactivity-inducing mechanism following intense sound exposure. They further suggest that blockade of NMDA receptors may offer a useful therapeutic approach to preventing induction of noise-induced hyperactivity-related hearing disorders, such as tinnitus and hyperacusis.
(Copyright © 2018 Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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