title: Effects of adenylate cyclase activation on electrical resistance of scala media.
abstract: Electrical resistance of scala media at the second turn of the guinea pig cochlea was measured while cochlear adenylate cyclase was activated by perilymphatic perfusion with 2 x 10(-4) M forskolin. The electrical resistance decreased from the pre-forskolin value (6.36 +/- 0.27 k omega to 5.22 +/- 0.33 k omega, n = 5), while the endocochlear potential (EP) increased from the pre-forskolin value (70.2 +/- 2.1 mV to 81.2 +/- 2.8 mV, n = 5). The time course of the electrical resistance change was more rapid than that of the EP change but almost identical to the time course of the change in the Cl- activity of the endolymph. The results suggest that the forskolin-induced decrease in the electrical resistance of the perilymph-endolymph barrier (presumably Reissner's membrane), and the consequent increase in Cl- flux into the endolymph may trigger EP elevation.
authors.affiliation: Department of Otolaryngology, Osaka University Medical School, Japan.
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 / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D002712:Chlorides / Q000378:metabolism; D003053:Cochlear Duct / Q000187:drug effects* / Q000201:enzymology / Q000502:physiology*; D005576:Colforsin / Q000008:administration & dosage / Q000494:pharmacology*; D017097:Electric Impedance; D004558:Electric Stimulation; D004789:Enzyme Activation; D006168:Guinea Pigs; D000860:Hypoxia / Q000201:enzymology / Q000503:physiopathology; D013997:Time Factors
chemical_list: D002712:Chlorides; D005576:Colforsin; D000262:Adenylyl Cyclases