title: Effects of ketanserin on the pacemaker activity of rabbit sinus node in vitro.
abstract: Electrophysiological effects of ketanserin on pacemaker activity of rabbit sinus node cells were studied using double-microelectrode voltage clamp method. Ketanserin (10(-5) mol/l) caused an increase in spontaneous cycle length accompanied by decreases in the maximum upstroke velocity of the action potential, the slope of the phase 4 depolarization and the action potential amplitude. On the current systems, ketanserin reduced the slow inward current (Isi) and the time-dependent potassium outward current (IK) in a dose-dependent manner. As for a decrease in the outward current, the agent did not change the steady-state activation of IK. These observations indicate that ketanserin does not have a specific effect on a single current system, but that the drug exerts an inhibitory effect on the electrical activity of the sinus node pacemaker cells.
authors.affiliation: 1st Department of Internal Medicine, Tottori University School of Medicine, Yonago, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Kotake
authors.forename: S
authors.initials: S
authors.lastname: Hirai
authors.forename: M
authors.initials: M
authors.lastname: Kobayashi
authors.forename: T
authors.initials: T
authors.lastname: Matsumoto
authors.forename: M
authors.initials: M
authors.lastname: Watanabe
authors.forename: J
authors.initials: J
authors.lastname: Hasegawa
authors.forename: H
authors.initials: H
authors.lastname: Mashiba
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D004594:Electrophysiology; D005260:Female; D066298:In Vitro Techniques; D007650:Ketanserin / Q000494:pharmacology*; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D015221:Potassium Channels / Q000187:drug effects; D011817:Rabbits; D012849:Sinoatrial Node / Q000166:cytology / Q000187:drug effects*
chemical_list: D015221:Potassium Channels; D007650:Ketanserin