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Involvement of Cl− transport in forskolin-induced elevation of endocochlear potential

1993; Elsevier BV; Volume: 71; Issue: 1-2 Linguagem: Inglês

10.1016/0378-5955(93)90017-u

1878-5891

Ikuo Kitano, Katsumi Doi, Nozomu Mori, Takashi Matsunaga,

Vestibular and auditory disorders

To determine the possible involvement of Cl- transport in the forskolin-induced endocochlear potential (EP) elevation, the effect of forskolin on the EP was examined in Cl(-)-free artificial perilymph (aPL) as well as in the presence of Cl- channel blockers. The perfusion of scala vestibuli (SV) with forskolin (200 microM) dissolved in Cl(-)-free aPL failed to produce an EP elevation, while SV perfusion of forskolin dissolved in normal aPL elevated the EP. The application of DPC and IAA-94 (blockers of cAMP-activated Cl- channel) into SV completely suppressed the forskolin-induced EP elevation, while niflumic acid (a Ca(2+)-activated Cl- channel blocker) failed to do so. IAA-94 applied into scala tympani (ST) did not suppress this EP elevation. The results suggest that adenylate cyclase may modulate the EP by changing Cl- transport between SV and scala media (SM) across Reissner's membrane.