The effect of quinine on outer hair cell shape, compliance and force.
Quinine intoxication causes a well-described syndrome that includes tinnitus, sensorineural hearing loss and vertigo. The pathophysiology of quinine's effects on hearing is unknown, but may include a peripheral component. The cochlear outer hair cell is known to be motile and to contribute force to amplify the vibration pattern of the organ of Corti. The outer hair cell is also a target of diseases involving tinnitus and sensorineural hearing loss, including salicylate intoxication. These effects may be mediated through changes either in motile force or in mechanical properties. Quinine's effects on outer hair cell motility and mechanical properties have therefore been examined in vitro. Quinine at 5.0 mM substantially decreased active force generation in isolated guinea pig cochlear outer hair cells. Isolated cells also elongated and dilated in diameter when exposed to 5.0 mM quinine. No consistent changes in mechanical properties were observed. 1.0 mM quinine was ineffective in either force reduction or elongation. Trifluoperazine, a calmodulin inhibitor, and ML-9, a blocker of myosin light chain kinases, were ineffective in blocking quinine-induced force reduction or elongation. Deferoxamine, a hydroxyl free radical scavenger, also failed to block either the force decrease or the elongation.
Department of Otolaryngology-Head and Neck Surgery, University of Texas Health Science Center at San Antonio, 78284-7777, USA.
J K
JK
Jarboe
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R
Hallworth
D000818:Animals; D001381:Azepines / Q000494:pharmacology; D002147:Calmodulin / Q000502:physiology; D003187:Compliance; D003676:Deferoxamine / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D016166:Free Radical Scavengers / Q000494:pharmacology; D006168:Guinea Pigs; D018072:Hair Cells, Auditory, Outer / Q000166:cytology / Q000187:drug effects* / Q000502:physiology*; D017665:Hydroxyl Radical / Q000378:metabolism; D009038:Motion; D009219:Myosin-Light-Chain Kinase / Q000502:physiology; D011803:Quinine / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D014268:Trifluoperazine / Q000494:pharmacology
D001381:Azepines; D002147:Calmodulin; D004791:Enzyme Inhibitors; D016166:Free Radical Scavengers; C056218:ML 9; D014268:Trifluoperazine; D017665:Hydroxyl Radical; D011803:Quinine; D009219:Myosin-Light-Chain Kinase; D003676:Deferoxamine