title: Augmentation of the delayed rectifier potassium current by ET A endothelin receptor in guinea pig atrial myocytes.
abstract: The role of ET(A) endothelin receptor (ET(A)R) in the regulation of the delayed rectifier potassium current (I(K)) was examined in guinea pig atrial myocytes. Application of ET-1 (10 nM) together with an ET(B)-receptor-selective antagonist, BQ-788 (300 nM), significantly increased the voltage-dependent activation of I(K) without affecting its half-activation voltage or the slope factor, while it suppressed the calcium current (I(CaL)) and displaced the time-independent background current to the outward direction. The data suggests that the augmentation of I(K) contributes to the ET(A)-receptor-mediated shortening of action potential duration, and hence to the negative inotropic response, in atria.
authors.affiliation: Division of Xenobiotic Metabolism and Disposition, National Institute of Health Sciences, Tokyo, Japan. kono@nihs.go.jp
authors.forename: Kageyoshi
authors.initials: K
authors.lastname: Ono
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000465:Algorithms; D000818:Animals; D002462:Cell Membrane / Q000502:physiology; D051668:Delayed Rectifier Potassium Channels; D004594:Electrophysiology; D065128:Endothelin Receptor Antagonists; D019332:Endothelin-1 / Q000494:pharmacology; D006168:Guinea Pigs; D006321:Heart / Q000502:physiology*; D066298:In Vitro Techniques; D007700:Kinetics; D008564:Membrane Potentials / Q000502:physiology; D009206:Myocardium / Q000166:cytology; D009842:Oligopeptides / Q000494:pharmacology; D018408:Patch-Clamp Techniques; D010880:Piperidines / Q000494:pharmacology; D015221:Potassium Channels / Q000187:drug effects / Q000502:physiology*; D024642:Potassium Channels, Voltage-Gated; D044022:Receptor, Endothelin A; D017466:Receptors, Endothelin / Q000502:physiology*
chemical_list: D051668:Delayed Rectifier Potassium Channels; D065128:Endothelin Receptor Antagonists; D019332:Endothelin-1; D009842:Oligopeptides; D010880:Piperidines; D015221:Potassium Channels; D024642:Potassium Channels, Voltage-Gated; D044022:Receptor, Endothelin A; D017466:Receptors, Endothelin; C086539:BQ 788