Effects of volatile anesthetics on elastic stiffness in isometrically contracting ferret ventricular myocardium.
The effects of halothane, isoflurane, and sevoflurane on elastic stiffness, which reflects the degree of cross-bridge attachment, were studied in intact cardiac muscle. Electrically stimulated (0.25 Hz, 25 degrees C), isometrically twitching right ventricular ferret papillary muscles (n = 15) at optimal length (L(max)) were subjected to sinusoidal length oscillations (40 Hz, 0.25- 0.50% of L(max) peak to peak). The amplitude and phase relationship with the resulting force oscillations was decomposed into elastic and viscous components of total stiffness in real time. Increasing extracellular Ca(2+) concentration in the presence of anesthetics to produce peak force equal to control increased elastic stiffness during relaxation, which suggests a direct effect of halothane and sevoflurane on cross bridges.
Bartunek
Anna E
AE
Department of Anesthesiology, Mayo Foundation, Rochester, Minnesota 55905, USA.
Claes
Victor A
VA
Housmans
Philippe R
PR
D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000378:metabolism; D004548:Elasticity; D005110:Extracellular Space / Q000378:metabolism; D005289:Ferrets; D006221:Halothane / Q000494:pharmacology*; D007530:Isoflurane / Q000494:pharmacology*; D007537:Isometric Contraction / Q000187:drug effects*; D008297:Male; D008738:Methyl Ethers / Q000494:pharmacology*; D009200:Myocardial Contraction / Q000187:drug effects*; D009994:Osmolar Concentration; D000077149:Sevoflurane; D016276:Ventricular Function / Q000187:drug effects*
D018685:Anesthetics, Inhalation; D008738:Methyl Ethers; D000077149:Sevoflurane; D007530:Isoflurane; D002118:Calcium; D006221:Halothane