title: Myocardial effects of halothane and isoflurane in senescent rats.
abstract: BACKGROUND
  Aging is associated with marked alterations in myocardial contraction and relaxation, whereas halogenated anesthetics depress myocardial contractility. However, their effects on aging myocardium are unknown.
  
  
  METHODS
  Mechanical variables of left ventricular papillary muscles from adult and senescent rats (29 degrees C; pH 7.40; Ca2+ 1.0 or 0.5 mM; stimulation frequency, 12 pulses/min) were studied. The expression of genes coding for the alpha and beta-myosin heavy chain (MHC) and Ca2+ -ATPase of the sarcoplasmic reticulum (SR) were studied. The effects of halothane and isoflurane were studied. The inotropic effects were compared under low and high loads, using the maximum unloaded shortening velocity (Vmax) and maximum isometric active force (AF). The lusitropic effects were compared in isotonic and isometric conditions.
  
  
  RESULTS
  Senescent rats had a decrease in contraction and relaxation velocities, associated with a reexpression of beta-MHC mRNAs and a decrease in SR Ca2+ -ATPase mRNAs. Halothane induced a lower negative inotropic effect in senescent rats (1.5 vol%, AF: 53 +/- 14% vs. 39 +/- 12% of baseline values; P < 0.01) whereas isoflurane induced a similar negative inotropic effect (1.5 vol%, AF: 81 +/- 7% vs. 87 +/- 7% of baseline values; NS). Halothane induced a negative lusitropic effect in isotonic conditions in adult, but not in senescent, rats.
  
  
  CONCLUSIONS
  The inotropic and lusitropic effects of halothane were less important in senescent than in adult rats, whereas the effects of isoflurane were similar. These differences are probably related to differences in SR function and in the effects of halogenated anesthetics on the SR.
authors.affiliation: Laboratory of Anesthesiology, University René Descartes, Paris, France.
authors.forename: Sandrine
authors.initials: S
authors.lastname: Rozenberg
authors.forename: Sophie
authors.initials: S
authors.lastname: Besse
authors.forename: Benoît
authors.initials: B
authors.lastname: Vivien
authors.forename: Pierre
authors.initials: P
authors.lastname: Coriat
authors.forename: Bruno
authors.initials: B
authors.lastname: Riou
mesh_terms: D000375:Aging / Q000502:physiology*; D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D000818:Animals; D004305:Dose-Response Relationship, Drug; D006221:Halothane / Q000494:pharmacology*; D007530:Isoflurane / Q000494:pharmacology*; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D018685:Anesthetics, Inhalation; D007530:Isoflurane; D006221:Halothane