title: Involvement of Cl- transport in forskolin-induced elevation of endocochlear potential.
abstract: 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.
authors.affiliation: Department of Otolaryngology, Nara Medical University, Japan.
authors.forename: I
authors.initials: I
authors.lastname: Kitano
authors.forename: K
authors.initials: K
authors.lastname: Doi
authors.forename: N
authors.initials: N
authors.lastname: Mori
authors.forename: T
authors.initials: T
authors.lastname: Matsunaga
mesh_terms: D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D001692:Biological Transport; D018118:Chloride Channels / Q000187:drug effects; D002712:Chlorides / Q000378:metabolism*; D003051:Cochlea / Q000187:drug effects* / Q000378:metabolism; D003053:Cochlear Duct / Q000187:drug effects* / Q000378:metabolism; D005576:Colforsin / Q000494:pharmacology*; D005072:Evoked Potentials, Auditory / Q000187:drug effects*; D006016:Glycolates / Q000494:pharmacology; D006168:Guinea Pigs; D010498:Perilymph / Q000187:drug effects / Q000378:metabolism; D062367:ortho-Aminobenzoates / Q000494:pharmacology
chemical_list: D018118:Chloride Channels; D002712:Chlorides; D006016:Glycolates; D062367:ortho-Aminobenzoates; D005576:Colforsin; C015765:MK 473; C001209:fenamic acid; D000262:Adenylyl Cyclases