Seminars & Events
Friday, October 4, 2013: Dr. Laurie Ryan, SMCM '86 (National Institute on Aging) will speak on "Alzheimer's Disease: Targets and Treatments" at 3:00 pm in Goodpaster Hall 195.
Monday, October 21, 2013: Dr. Greg Elmer (University of Maryland Baltimore) will speak on "Domains and Constructs in Motivation: Where Does the Habenula Fit In?" at 4:45 pm in Goodpaster Hall 195.
Friday, October 25, 2013: Dr. Terry Davidson (American University) will speak on "Why We Overeat and Become Obese? It Could be What We Think!" at 3:00 pm in Goodpaster Hall 195.
Dr. Gwen Calhoon '06 recently received her Ph.D. in Neuroscience from the University of Maryland Baltimore, and was inducted into Nu Rho Psi.
Ramcharitar, J.U., Smist, M.C., Selckmann, G.M., and Traven, S.A. (2009, October). Effects of gentamicin on the goldfish auditory system. Poster presented at the Society for Neuroscience Annual Meeting, Chicago, IL.
Over the last few years, the zebrafish lateral line system has been successfully adopted for the study of pharmaceutical agents known to be ototoxic and otoprotective in humans. However, relatively few investigations have examined ototoxicity in the auditory systems of fishes. As such, we assessed the effects of gentamicin on both the structure and function of the goldfish inner ear, which has a similar configuration to that of the zebrafish. Specifically, changes in sensory hair cell densities of the otolithic end organs (i.e. saccule, lagena and utricle), as well as in auditory evoked potentials (AEPs) were quantified after the administration of gentamicin. Fish were injected once per day (100 mg/kg) for four consecutive days and one day after the final injection, AEPs were determined for the frequency range 100 - 1000 Hz. Fish were then euthanized, fixed overnight with 2.5% glutaraldehyde and auditory epithelia were harvested after washing the tissues with phosphate buffer. Phalloidin was used to visualize ciliary bundles with conventional fluorescence microscopy. All of the treated fish selected for this study demonstrated behavioral deficits including vestibular and feeding problems. Significant reductions in hair cell densities in the striola regions of utricles and lagenae were observed (n = 7, p < 0.05). In this regard, striola hair cells have previously been described as Type I-like. Hair cell ciliary bundle loss was also observed in saccular sensory epithelia. With regard to auditory function, auditory thresholds were found to be elevated in injected fish, indicating that hearing was adversely affected by gentamicin. These data support the use of the teleost inner ear for the screening of new drugs for potential ototoxicity. We also demonstrated that AEP measurements offer rapid assessment of ototoxic effects in a model fish species.