title: Effects of propofol on contractile response and electrophysiological properties in single guinea-pig ventricular myocyte.
abstract: Effects of propofol on contractile response, action potential, resting membrane potential and L-type voltage-dependent calcium channel current were examined in guinea-pig single cardiac myocyte. Propofol (10(-4) M) inhibited contractile response induced by electrical stimulation (83.6% of control, n = 5), but did not change the resting membrane potential. On the other hand, propofol reduced the overshoot of action potential (10(-4) M), and shortened the duration of action potential (10(-5) and 10(-4) M). Whole-cell voltage clamp experiment showed inhibition of L-type calcium channel current (ICa, 10(-5) M: 90.8+/-1.39, 10(-4) M: 83.4+/-1.53% of control, n = 5). In addition, propofol showed use-dependent block of ICa. It is concluded that negative inotropic effect of propofol is caused by suppression of action potential, and that inhibition of ICa plays a role in shortening of the duration of action potential.
authors.affiliation: Department of Anaesthesiology, Toyama Medical and Pharmaceutical University, Faculty of Medicine, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Shigemura
authors.forename: N
authors.initials: N
authors.lastname: Hatakeyama
authors.forename: N
authors.initials: N
authors.lastname: Shibuya
authors.forename: M
authors.initials: M
authors.lastname: Yamazaki
authors.forename: A
authors.initials: A
authors.lastname: Masuda
authors.forename: F S
authors.initials: FS
authors.lastname: Chen
authors.forename: Y
authors.initials: Y
authors.lastname: Momose
authors.forename: Y
authors.initials: Y
authors.lastname: Ito
mesh_terms: D000200:Action Potentials / Q000187:drug effects* / Q000502:physiology; D018686:Anesthetics, Intravenous / Q000494:pharmacology*; D000818:Animals; D015220:Calcium Channels / Q000187:drug effects / Q000502:physiology; D005260:Female; D006168:Guinea Pigs; D006352:Heart Ventricles / Q000166:cytology / Q000187:drug effects*; D066298:In Vitro Techniques; D009200:Myocardial Contraction / Q000187:drug effects* / Q000502:physiology; D009206:Myocardium / Q000166:cytology*; D018408:Patch-Clamp Techniques; D015742:Propofol / Q000494:pharmacology*; D016276:Ventricular Function
chemical_list: D018686:Anesthetics, Intravenous; D015220:Calcium Channels; D015742:Propofol