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Updated: Aug 18, 2026

Optical Mapping of Intra-Sarcoplasmic Reticulum Ca2+ and Transmembrane Potential in the Langendorff-perfused Rabbit Heart
09:26

Optical Mapping of Intra-Sarcoplasmic Reticulum Ca2+ and Transmembrane Potential in the Langendorff-perfused Rabbit Heart

Published on: September 10, 2015

Calcium transport by cardiac sarcoplasmic reticulum: modulation of halothane action by substrate concentration and pH

T J Blanck, M Thompson

    Anesthesia and Analgesia
    |June 1, 1981
    PubMed

    Insights

    Halothane

    Area of Science:

    • Cardiology
    • Anesthesiology
    • Biochemistry

    Background:

    • Cardiac sarcoplasmic reticulum (SR) calcium transport is crucial for myocardial function.
    • Anesthetic agents like halothane can affect cardiac contractility.
    • Understanding halothane's impact on SR calcium handling is key to cardiac depression mechanisms.

    Purpose of the Study:

    • To investigate the effect of halothane on calcium transport by the cardiac sarcoplasmic reticulum.
    • To determine if the SR is a site of anesthetic-induced myocardial depression.

    Main Methods:

    • Studied calcium transport in cardiac SR under varying halothane concentrations.
    • Assessed effects of halothane on adenosine triphosphate (ATP) kinetics (Km, Vmax).
    • Measured steady-state calcium levels in SR at different pH and substrate concentrations.

    Main Results:

    • Halothane exhibited biphasic effects on calcium transport, causing both stimulation (800%) and inhibition (500%).
    • Halothane altered ATP kinetics, decreasing Km and Vmax for ATP.
    • At pH 6.9, halothane reduced SR calcium by 33%; no effect was observed at pH 7.3.

    Conclusions:

    • The cardiac SR is unlikely to be the primary site of halothane-induced myocardial depression in healthy hearts with normal substrate and pH.
    • In ischemic conditions (low pH, low substrate), halothane's interaction with SR calcium transport may contribute to reduced myocardial contractility due to decreased Ca2+ availability.

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