[Abstract Title]. - Society for Neuroscience

Program#/Poster#: 259.6/BB2
Topic: D.02.a. Mechanoreceptors and cochlea
Support: EuroHear FP5 512063
Title: Cochlear hair cell currents and tuning in adult rats
Authors: J. HERING 1,2 , *C. PETIT 1,2,3 ;
1 INSERM UMRS 587, Inst. Psteur, Paris Cedex 15, France; 2 Univ. Pierre et Marie Curie, Paris
VI, France; 3 Collège de France, Paris, France
Abstract: The sensory cells (hair cells) of the mammalian cochlea are involved for sound
amplification (outer hair cells) and transduction into electrical signals (inner hair cells). The
motion of the sensory epithelium (organ of Corti) is driven by the movement of the underlying
basilar membrane. In non-mammalian species, auditory hair cells display electrical tuning, which
enables each hair cell to respond preferentially to a “best frequency” of the basilar membrane
movement (tonotopy). In mammals, electrical tuning of the hair cell response has neither been
shown nor totally excluded. To address this issue, we have used the hemicochlea technique that
preserves the integrity of the organ of Corti. Our setup combines electrophysiology,
interferometry, and IR observation of the preparation. The recordings were made at 35-37°C in
Wistar rats aged from P25 to 6 months. The hair cells were stimulated by the means of a tungsten
probe (driven by a piezoelectrical actuator) applied on the basilar membrane, and delivering sine
stimulations comparable to pure tones. Displacement and velocity of the basilar membrane were
measured with a commercial interferometer (Polytec, France). The receptor potentials and
currents of hair cells were recorded with the patch-clamp technique in whole-cell configuration.
Because the stimulation and receptor potential acquisition were under computer control, we were
able to determine the best frequency of each patched hair cell, which allowed us to record
mechanoelectrical currents and receptor potentials at this particular frequency. In addition, the
different hair cell conductances could be characterized by their pharmacological and biophysical
properties. This unique system, combining different techniques, allowed us to study for the first
time hair cell properties along the entire tonotopic axis of a mature cochlea.
Disclosures: J. Hering, None; C. Petit , None.
Poster
259. Cochlear Mechanoreceptors
Time: Sunday, November 16, 2008, 1:00 pm - 5:00 pm
Program#/Poster#: 259.7/BB3