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Chlorpromazine alters outer hair cell electromotility
A J Lue1, H B Zhao, W E Brownell
1Bobby Ray Alford Department of Otorhinolaryngology and Communicative Sciences, Baylor College of Medicine, Houston, TX, USA.
Summary
Chlorpromazine alters outer hair cell (OHC) electromotility by shifting the voltage at peak capacitance. This antipsychotic medication changes OHC function without altering response magnitude, potentially impacting hearing.
Area of Science:
- Auditory Neuroscience
- Cellular Electrophysiology
- Pharmacology
Background:
- Outer hair cells (OHCs) are crucial for hearing, converting electrical signals into mechanical forces to amplify sound.
- Understanding how drugs affect OHC function is key to addressing hearing disorders.
Purpose of the Study:
- To investigate the impact of chlorpromazine, an antipsychotic, on the electromotility of OHCs.
- To determine if chlorpromazine alters the voltage-dependent mechanical responses of OHCs.
Main Methods:
- Isolated guinea pig OHCs were studied using whole-cell patch-clamp recordings.
- Electromotile responses were measured after perfusion with varying concentrations of chlorpromazine.
Main Results:
- Chlorpromazine caused a dose-dependent, reversible depolarization of the voltage at peak capacitance (V(pkCm)).
- The gain of OHC electromotility remained maximal near V(pkCm) post-treatment.
- Unlike other agents, chlorpromazine did not alter peak capacitance (Cm(pk)), a measure of electromotile gain magnitude.
Conclusions:
- Chlorpromazine modifies the voltage setpoint for maximal OHC electromotile gain.
- The drug alters OHC voltage regulation without affecting the overall force generation capacity.