Endocochlear potential and endolymphatic K+ changes induced by gap junction blockers.
OBJECTIVE
To examine the effects of gap junction blockers on the endocochlear potential (EP) and endolymphatic potassium concentration ([K(+)](e)).


METHODS
The EP and [K(+)](e) were monitored using double-barreled ion-selective microelectrodes in the second turn of the guinea pig cochlea during perilymphatic perfusion.


RESULTS
When the perilymphatic scalae of the cochlea were perfused with artificial perilymph containing 10 mM n-heptanol the EP was decreased by -8.8+/-1.4 mV (n=10), and this was accompanied by a decline in the [K(+)](e) of -6.7+/-2.1 mM (n=6). Perilymphatic application of 10 mM hexanol also produced declines in both the EP and [K(+)](e). In control studies, perilymphatic perfusion with 10 mM ethanol showed no remarkable changes in either the EP or [K(+)](e). Anoxia during perfusion with heptanol resulted in the generation of a negative EP, similar to the situation in controls.


CONCLUSIONS
A decline in the EP together with a lowering of [K(+)](e) induced by long-chain n-alkanols, which act as gap junction blockers, may be explained by an interruption in potassium ion transport related to a gap junction dysfunction.
Suzuki
Masaaki
M
Department of Otorhinolaryngology-Head and Neck Surgery, Tohoku University Graduate School of Medicine, Sendai, Japan. msuzuki@sleep.ac
Kikuchi
Toshihiko
T
Ikeda
Katsuhisa
K
D000438:Alcohols / Q000494:pharmacology*; D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D003051:Cochlea / Q000187:drug effects / Q000502:physiology*; D003055:Cochlear Microphonic Potentials / Q000187:drug effects* / Q000502:physiology; D000431:Ethanol / Q000494:pharmacology; D017629:Gap Junctions / Q000187:drug effects* / Q000502:physiology; D006168:Guinea Pigs; D019850:Heptanol / Q000494:pharmacology; D000441:Hexanols / Q000494:pharmacology; D010477:Perfusion / Q000379:methods; D010498:Perilymph / Q000502:physiology; D011188:Potassium / Q000378:metabolism*; D015221:Potassium Channels / Q000378:metabolism
D000438:Alcohols; D000441:Hexanols; D015221:Potassium Channels; D000431:Ethanol; C036260:1-hexanol; D019850:Heptanol; D011188:Potassium