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BP: Fachverband Biologische Physik

BP 32: Physics of Cells III

BP 32.9: Vortrag

Freitag, 30. März 2012, 11:45–12:00, H 1028

Temperature-dependent auditory tuning can arise from transduction channel gating — •Björn Nadrowski¹ and Martin Göpfert² — ¹Theoretische Physik, Universität des Saarlandes, 66123 Saarbrücken, Germany — ²Dept. of Cellular Neurobiology, Schwann-Schleiden Research Centre, Julia-Lermontowa-Weg 3, 37077 Göttingen, Germany

Ears achieve their exquisite sensitivity by means of active mechanical feedback. This feedback depends on metabolic energy, which might explain why temperature affects the mechanical tuning of ears. Spontaneous otoacoustic emissions from reptile ears, for example, get faster when the ambient temperature rises, and self-sustained oscillations in mosquito ears likewise speed up when temperature is increased. By analyzing the resulting frequency-shifts in terms of the Arrhenius equation, activation energies of the molecular motors that promote the mechanical feedback have been deduced. Here, we show that apart from motor characteristics the gating of auditory transduction channels can influence auditory mechanics in a temperature-dependent manner, providing an alternative explanation for the temperature-dependent tuning of ears. The link between auditory tuning and channel gating is established using physical models of sensory hair bundles and the Drosophila hearing organ. In both systems, opening or closing all the transduction channels requires larger stimulus forces as temperature rises, decreasing mechanical nonlinearities and causing best-frequency shifts.