title: Decrease of prestin expression by increased potassium concentration in organotypic cultures of the organ of Corti of newborn rats.
abstract: Prestin is the motor protein of the outer hair cells of the organ of Corti and a key factor in ensuring a high sensitivity level of mammalian hearing. In the present study, we examined the effects of increased extracellular potassium (K(+)) concentration on the expression of prestin mRNA and the transcription factors Gata-3 and Carf in the organotypic culture of the organ of Corti of newborn rats. Mannitol and NaCl were used to analyze possible effects of hyperosmotic stress or ion-specific changes, respectively. An increase in prestin expression by a factor of 1.5-2.0 was seen in cultures grown in the presence of 5mM K(+). Potassium concentration of 35 and 55 mM induced a parallel decrease in prestin and Carf expression, but Gata-3 expression increased. Mannitol had no effect on gene expression whereas increased NaCl concentrations decreased prestin, but not Carf expression. The data suggest that chronic depolarization might decrease the prestin expression and possibly contribute to hearing loss and tinnitus.
authors.affiliation: Molecular Biology Research Laboratory, Department of Otorhinolaryngology CCM, Charité - Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Birgit
authors.initials: B
authors.lastname: Mazurek
authors.forename: Julia
authors.initials: J
authors.lastname: Fuchs
authors.forename: Kerstin
authors.initials: K
authors.lastname: Stute
authors.forename: Maximilian
authors.initials: M
authors.lastname: Angerstein
authors.forename: Nyamaa
authors.initials: N
authors.lastname: Amarjargal
authors.forename: Heidi
authors.initials: H
authors.lastname: Olze
authors.forename: Johann
authors.initials: J
authors.lastname: Gross
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D027321:Anion Transport Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics* / Q000378:metabolism; D018072:Hair Cells, Auditory, Outer / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D009924:Organ Culture Techniques; D009925:Organ of Corti / Q000166:cytology / Q000254:growth & development* / Q000502:physiology*; D011188:Potassium / Q000378:metabolism / Q000502:physiology*; D051381:Rats; D000076988:Sulfate Transporters; D013997:Time Factors
chemical_list: D027321:Anion Transport Proteins; C409207:Slc26a5 protein, rat; D000076988:Sulfate Transporters; D011188:Potassium