title: Arachidonic acid-induced channel- and carrier-type ion transport across planar bilayer lipid membranes.
abstract: Transmembrane ion transport by arachidonic acid (AA) through bilayer lipid membranes (BLMs) was investigated by means of electrochemical measurements to provide a basis for designing a sensor membrane. We found that AA induces a channel-type current, in addition to a carrier-type current, across planar BLMs. A linear relation between the logarithmic value of the AA concentration and the current responses (given as integrated currents) was observed for a carrier-type current, while a sigmoid relation was found for a channel-type current. Although AA transports Na+, Ca2+ and Mg2+ and exhibits ion selectivity between Na+ and Mg2+ for the carrier-type current, ion transport for the channel-type current was non-selective. It was found that ion transport via the channel mechanism occurs frequently for AA, while channel-type currents were only occasionally observed for y-linolenic acid and prostaglandin D2. No channel-type currents were induced by other fatty acids (oleic, linoleic, stearic, myristic, eicosapentanoic and docosahexanoic acids) and metabolites of AA (12-HETE and 5-HETE). The carrier-type ion transport occurs selectively to these compounds if the concentration is below 1.0 microM. These results suggest that AA selectively facilitates an ion flux through the BLMs, generating channel-type and/or carrier-type currents, which can be used as a measure of the AA concentration.
authors.affiliation: Department of Chemistry, College of Humanities and Sciences, Nihon University, Sakurajousui, Setagaya, Tokyo 156-8550, Japan.
authors.forename: Ayumi
authors.initials: A
authors.lastname: Hirano
authors.forename: Yuko
authors.initials: Y
authors.lastname: Namatame
authors.forename: Eiichi
authors.initials: E
authors.lastname: Wakaizumi
authors.forename: Yuka
authors.initials: Y
authors.lastname: Matsuno
authors.forename: Masao
authors.initials: M
authors.lastname: Sugawara
mesh_terms: D016718:Arachidonic Acid / Q000494:pharmacology*; D015374:Biosensing Techniques / Q000379:methods; D002118:Calcium / Q000493:pharmacokinetics; D004305:Dose-Response Relationship, Drug; D004563:Electrochemistry / Q000379:methods; D005227:Fatty Acids / Q000494:pharmacology; D006579:Heterozygote; D007473:Ion Channels; D017136:Ion Transport / Q000187:drug effects*; D008051:Lipid Bilayers / Q000378:metabolism; D008274:Magnesium / Q000493:pharmacokinetics; D015230:Prostaglandin D2 / Q000494:pharmacology; D012964:Sodium / Q000493:pharmacokinetics; D017965:gamma-Linolenic Acid / Q000494:pharmacology
chemical_list: D005227:Fatty Acids; D007473:Ion Channels; D008051:Lipid Bilayers; D016718:Arachidonic Acid; D017965:gamma-Linolenic Acid; D012964:Sodium; D008274:Magnesium; D015230:Prostaglandin D2; D002118:Calcium