gms | German Medical Science

80th Annual Meeting of the German Society of Oto-Rhino-Laryngology, Head and Neck Surgery

German Society of Oto-Rhino-Laryngology, Head and Neck Surgery

20.05. - 24.05.2009, Rostock

Can GABApentin improve the age dependent elevation of thresholds determined by a forward masking paradigm in gerbils?

Meeting Abstract

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  • corresponding author Otto Gleich - ENT-Department University of Regensburg, Regensburg, Germany
  • author Jürgen Strutz - ENT-Department University of Regensburg, Regensburg, Germany

German Society of Oto-Rhino-Laryngology, Head and Neck Surgery. 80th Annual Meeting of the German Society of Oto-Rhino-Laryngology, Head and Neck Surgery. Rostock, 20.-24.05.2009. Düsseldorf: German Medical Science GMS Publishing House; 2009. Doc09hno029

DOI: 10.3205/09hno029, URN: urn:nbn:de:0183-09hno0290

Published: July 22, 2009

© 2009 Gleich et al.
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Outline

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The aim of the present study was to analyze if GABApentin can affect thresholds determined by a forward masking paradigm in gerbils. Thresholds for a short 20ms probe following 2.5ms after a 400ms masker (both 2.85 kHz) that was presented at 40 dBSPL were determined in each of 13 gerbils for 4 different conditions. These conditions were before (pre) and 2 weeks after (post) the animals were treated with GABApentin and under 115 and 350 mg/kg/day GABApentin that was administered each morning via the drinking water. The age of the animals varied between 1 and 4 years with 5 animals younger and 8 older than 30 months. A repeated measure analysis of masked thresholds for the factors age and condition revealed a highly significant effect of age (young: 35 dBSPL, old 45.5 dBSPL; p < 0.001) while mean masked thresholds did not differ between the 4 conditions of medication (39.1 – 41.3 dBSPL, p = 0.129). However, the analysis indicated a significant interaction between age group and condition (p = 0.012) necessitating a separate analysis of the conditions within each age group. Pair wise Tukey tests in the group of young animals revealed that masked thresholds during 350 mg/kg/day GABApentin were significantly higher (38.3 dBSPL) than before (32.3 dBSPL) or after (33.5 dBSPL) GABApentin treatment (p < 0.05) while all other combinations did not differ significantly (p > 0.05). In the group of old animals there was no significant difference between any pair of treatment conditions (p > 0.485); GABApentin had no effect on masked thresholds in old gerbils.

Although GABApentin was originally designed as a GABA analogue it rather seems to affect voltage gated Ca2+ channels. The elevated masked thresholds during GABApentin treatment in young animals suggests that voltage gated Ca2+ channels are involved in sound processing characterized by the forward masking paradigm. In addition to the hypothesis of impaired inhibitory transmitter function, the elevation of masked thresholds in old gerbils could reflect changes in the function of voltage gated Ca2+ channels.

Supported by the DFG Str275/4-5. We thank Dr. J.-Th. Fränzer, S. Kopetschek, U. Schreiter and C. Woegerbauer for help with data collection.