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).Material and 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 b...