[Outward potassium currents in isolated Deiters' cells of guinea pig cochlea].
OBJECTIVE
To study potassium currents in isolated Deiters' cells of guinea pig cochlea.


METHODS
Potassium currents in Deiters' cells in normal external solution, in external solutions with different K+ concentrations effecting on reversal potentials and outward potassium currents, 4-aminopyridine (4-AP) and tetraethylammonium (TEA) blocking components of outward potassium currents and kinetics of activation and inactivation of potassium ion channels were studied using the whole cell variant of the patch clamp technique.


RESULTS
Isolated Deiters' cells could possess voltage dependent, outwardly rectifying ion channel which was K+ selective. Existence of two separate types of K+ channels or their closed and open states was suggested by effects of 4-AP and TEA. Activation and inactivation of ion channels were described by Boltzmman equation. Voltage dependent inward Ca2+ current could not be detected.


CONCLUSIONS
Outwardly rectifying potassium in Deiters' cells could buffer extracellular K+ in the small space between Deiters' cells and outer hair cells or neural fibers and alter the stiffness of Deiters' cells, which as a result might influence cochlear mechanics.
Yang
J
J
Department of Otorhinolaryngology, Union Hospital of Tongji Medical University, Wuhan 430022, China. yangjun67@263.net
Wang
J
J
D015761:4-Aminopyridine / Q000494:pharmacology; D000818:Animals; D003051:Cochlea / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology*; D011188:Potassium / Q000494:pharmacology*; D026902:Potassium Channel Blockers / Q000494:pharmacology; D015221:Potassium Channels / Q000187:drug effects / Q000502:physiology*; D019789:Tetraethylammonium / Q000494:pharmacology
D026902:Potassium Channel Blockers; D015221:Potassium Channels; D019789:Tetraethylammonium; D015761:4-Aminopyridine; D011188:Potassium