Table of Contents
ISRN Otolaryngology
Volume 2011, Article ID 204804, 8 pages
http://dx.doi.org/10.5402/2011/204804
Research Article

Assessment of Styrene Oxide Neurotoxicity Using In Vitro Auditory Cortex Networks

1Department of Speech and Hearing Sciences, University of North Texas, P.O. Box 305010, Denton, TX 76203-5010, USA
2Center for Network Neuroscience, University of North Texas, P.O. Box 305010, Denton, TX 76203-5010, USA
3Department of Biological Sciences, University of North Texas, P.O. Box 305010, Denton, TX 76203-5010, USA

Received 24 May 2011; Accepted 6 July 2011

Academic Editor: A. Bath

Copyright © 2011 Kamakshi V. Gopal et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Styrene oxide (SO) (C8H8O), the major metabolite of styrene (C6H5CH=CH2), is widely used in industrial applications. Styrene and SO are neurotoxic and cause damaging effects on the auditory system. However, little is known about their concentration-dependent electrophysiological and morphological effects. We used spontaneously active auditory cortex networks (ACNs) growing on microelectrode arrays (MEA) to characterize neurotoxic effects of SO. Acute application of 0.1 to 3.0 mM SO showed concentration-dependent inhibition of spike activity with no noticeable morphological changes. The spike rate IC50 (concentration inducing 50% inhibition) was 5 1 1 ± 6 0 μM ( 𝑛 = 1 0 ). Subchronic (5 hr) single applications of 0.5 mM SO also showed 50% activity reduction with no overt changes in morphology. The results imply that electrophysiological toxicity precedes cytotoxicity. Five-hour exposures to 2 mM SO revealed neuronal death, irreversible activity loss, and pronounced glial swelling. Paradoxical “protection” by 40 μM bicuculline suggests binding of SO to GABA receptors.