title: Effects of nitrous oxide on contractility, relaxation and the intracellular calcium transient of isolated mammalian ventricular myocardium.
abstract: The effects of nitrous oxide on variables of contractility and relaxation were analyzed in isolated ferret right ventricular papillary muscles. Each mechanical variable, in isometric, isotonic, and zero-load-clamped twitches, was compared to the average value of that variable in control conditions (50% nitrogen in oxygen), before and after equilibration with 20%, 30% and 50% nitrous oxide in 50% oxygen. Nitrous oxide caused a concentration-dependent decrease in contractility under all loading conditions, with minor changes in relaxation. The intracellular calcium transient was detected with the Ca(++)-regulated photoprotein aequorin. The change in aequorin luminescence on exposure to nitrous oxide suggests that the negative inotropic effect of nitrous oxide is due to a decrease in calcium availability with no effect on myofibrillar responsiveness to calcium.
authors.affiliation: Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota.
authors.forename: E G
authors.initials: EG
authors.lastname: Carton
authors.forename: L A
authors.initials: LA
authors.lastname: Wanek
authors.forename: P R
authors.initials: PR
authors.lastname: Housmans
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D004558:Electric Stimulation; D005289:Ferrets; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000378:metabolism; D009200:Myocardial Contraction / Q000187:drug effects*; D009609:Nitrous Oxide / Q000494:pharmacology*; D010100:Oxygen / Q000494:pharmacology
chemical_list: D009609:Nitrous Oxide; D010100:Oxygen; D002118:Calcium