Joseph Santos-Sacchi, PhD
Research & Publications
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Research Summary
The exquisite sensitivity and frequency resolving power of the mammalian inner ear depends upon interactions between the two receptor cells of the organ of Corti, inner (IHC) and outer (OHC) hair cells. While inner hair cells appear to function solely as receptors of acoustic information, OHC’s function both as receptors and effectors, producing motile responses as a function of transmembrane potential fluctuations.
These motile responses modify the mechanical input to the inner hair cells which receive the majority of afferent innervation, thereby enhancing the gross frequency tuning afforded by basilar membrane mechanics. Dr. Joseph Santos-Sacchi studies the effector role of the OHC with electrophysiological (patch clamp) and displacement measurement techniques using isolated OHCs from the guinea pig. He also works on the motor protein (prestin) responsible for the cells’ mechanical activity, utilizing mutational analysis and expression systems to understand how it works.
Specialized Terms: Mammalian inner ear
Coauthors
Research Interests
Hair Cells, Auditory; Ear, Inner; Neurosciences; Otolaryngology; Physiology
Selected Publications
- Determination of cell capacitance using the exact empirical solution of partial differential Y/partial differential Cm and its phase angle.Santos-Sacchi J. Determination of cell capacitance using the exact empirical solution of partial differential Y/partial differential Cm and its phase angle. Biophysical Journal 2004, 87: 714-27. PMID: 15240504, PMCID: PMC1304394, DOI: 10.1529/biophysj.103.033993.
- Control of mammalian cochlear amplification by chloride anions.Santos-Sacchi J, Song L, Zheng J, Nuttall AL. Control of mammalian cochlear amplification by chloride anions. The Journal Of Neuroscience : The Official Journal Of The Society For Neuroscience 2006, 26: 3992-8. PMID: 16611815, PMCID: PMC6673883, DOI: 10.1523/JNEUROSCI.4548-05.2006.
- En block C-terminal charge cluster reversals in prestin (SLC26A5): effects on voltage-dependent electromechanical activity.Bai JP, Navaratnam D, Samaranayake H, Santos-Sacchi J. En block C-terminal charge cluster reversals in prestin (SLC26A5): effects on voltage-dependent electromechanical activity. Neuroscience Letters 2006, 404: 270-5. PMID: 16839688, DOI: 10.1016/j.neulet.2006.05.062.
- Developmental expression of the outer hair cell motor prestin in the mouse.Abe T, Kakehata S, Kitani R, Maruya S, Navaratnam D, Santos-Sacchi J, Shinkawa H. Developmental expression of the outer hair cell motor prestin in the mouse. The Journal Of Membrane Biology 2007, 215: 49-56. PMID: 17415610, PMCID: PMC4154540, DOI: 10.1007/s00232-007-9004-5.
- Anion control of voltage sensing by the motor protein prestin in outer hair cells.Rybalchenko V, Santos-Sacchi J. Anion control of voltage sensing by the motor protein prestin in outer hair cells. Biophysical Journal 2008, 95: 4439-47. PMID: 18658219, PMCID: PMC2567960, DOI: 10.1529/biophysj.108.134197.
- Fast electromechanical amplification in the lateral membrane of the outer hair cell.Santos-Sacchi J, Navarrete E, Song L. Fast electromechanical amplification in the lateral membrane of the outer hair cell. Biophysical Journal 2009, 96: 739-47. PMID: 19167318, PMCID: PMC2716482, DOI: 10.1016/j.bpj.2008.10.015.
- Prestin's anion transport and voltage-sensing capabilities are independent.Bai JP, Surguchev A, Montoya S, Aronson PS, Santos-Sacchi J, Navaratnam D. Prestin's anion transport and voltage-sensing capabilities are independent. Biophysical Journal 2009, 96: 3179-86. PMID: 19383462, PMCID: PMC2718310, DOI: 10.1016/j.bpj.2008.12.3948.