Effects of volatile anesthetics on elastic stiffness in isometrically contracting ferret ventricular myocardium. |
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Authors: | Anna E Bartunek Victor A Claes Philippe R Housmans |
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Institution: | Department of Anesthesiology, Mayo Foundation, Rochester, Minnesota 55905, USA. |
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Abstract: | 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. |
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