Effects of change in concentration of calcium on myocardial contractility depressed by thiamylal and halothane.

Iwatsuki, Naofumi; Iwatsuki, Kazuhiko

doi:10.1620/tjem.120.1

Cited by 4 publications

(1 citation statement)

References 9 publications

(3 reference statements)

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“…The mode of interaction of Ca2+ and halothane in the myocardium appears to be more complex than simple competition for binding sites. Thus, competition has been demonstrated by double-reciprocal plot (16), but total reversal of halothane's negative inotropic effect is not possible even with large increases in extracellular Ca2+ concentration (17). Complete reversal of the negative inotropic effect of halothane by high concentrations of Ca2+ has so far been accomplished only under the condition of tetanus in the presence of caffeine (18).…”

Section: Discussionmentioning

confidence: 99%

Effect of Halothane on Rested-State and Potentiated-State Contractions in Rabbit Papillary Muscle

Komai¹,

Rusy²

1982

Anesthesia & Analgesia

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Effect of halothane on rested-state and potentiated-state contractions in rabbit papillary muscle: relationship to negative inotropic action. Anesth Analg 1982;61:403-9.The effect of halothane on the availability of different sources of activator calcium for myocardial contraction was evaluated in relationship to the negative inotropic effect of the anesthetic. This was studied in rabbit papillary muscle under various stimulation conditions that are known to vary the importance of one or another of two sources of Ca'+ for production of contraction. The rested-state contraction is known to depend primarily on the transsarcolemmal influx of Caz+ for its activation whereas the potentiated-state contraction is dependent largely on Ca'+ released from intracellular stores. In the presence of 0.6% halothane (gas phase) the rested-state and potentiated-state contractions were depressed (mean & SEM) 38% & 5% (n = 15) and 32% f 3% (n = 7), respectively (no statistically significant difference). Halothane accelerated the decay of the potentiated state, indicating that it stimulates the loss of Ca2+ from internal stores. Halothane also acted to slow the time course of force increase following restimulation of rested muscles, indicating that it inhibits the filling of internal stores. These observations suggest that the negative inotropic effect of halothane is caused by a combination of quantitatively similar effects of the anesthetic on the transsarcolemmal and intracellular sources of activator Ca".

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Section: Discussionmentioning

confidence: 99%

Effect of Halothane on Rested-State and Potentiated-State Contractions in Rabbit Papillary Muscle

Komai¹,

Rusy²

1982

Anesthesia & Analgesia

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Differential effects of halothane and enflurane on end-systolic pressure-diameter relationship in anesthetized, mechanically ventilated dogs

et al. 1994

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To clarify the difference of negative inotropic effects, we evaluated the effects of 0, 0.5, and 1 MAC halothane and enflurane on systolic performance in anesthetized, mechanically ventilated, vagotomized dogs. Left ventricular myocardial contractility was assessed by the slope of the end-systolic pressure-diameter relationship (EES), which have been reported to be independent of alterations in preload and afterload but sensitive to changes in myocardial contractility. Both anesthetics decreased heart rate and dose-dependently decreased left ventricular systolic pressure. Enflurane decreased heart rate and left ventricular systolic pressure more than an equivalent MAC of halothane. Both anesthetics increased left ventricular end-diastolic diameter without any change in % shortening of the left ventricular internal diameter. TheEES was decreased to a similar extent at both 0.5 and 1 MAC halothane. TheEES was decreased with increasing concentrations of enflurane. TheEES was significantly larger (P<0.05) with 1 MAC of halothane than with 1 MAC enflurane. These results suggest that halothane preserves myocardial contractility better than enflurane in the presence of fentanyl.

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Effect of Thiamylal on the Sensitivity of Glycerinated Cardiac Fibres to Calcium

Iwatsuki

Yasuda

Iwatsuki

1978

British Journal of Anaesthesia

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Clarification of the mechanisms of the myocardial depression produced by thiamylal was sought by studying the effect of thiamylal upon the sensitivity of contractile proteins to calcium (Ca2+), by using glycerinated muscle fibres from the canine right ventricle. The dose--response relationship between the concentration of Ca2+ and the force of contraction of the glycerinated cardiac muscle fibres was not shifted from the control curve by the administration of thiamylal 67 microgram ml-1. This result suggests that the changes in the sensitivity of contractile proteins to Ca2+ are not responsible for the depression of myocardial performance produced by thiamylal.

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Effects of change in concentration of calcium on myocardial contractility depressed by thiamylal and halothane.

Cited by 4 publications

References 9 publications

Effect of Halothane on Rested-State and Potentiated-State Contractions in Rabbit Papillary Muscle

Effect of Halothane on Rested-State and Potentiated-State Contractions in Rabbit Papillary Muscle

Differential effects of halothane and enflurane on end-systolic pressure-diameter relationship in anesthetized, mechanically ventilated dogs

Effect of Thiamylal on the Sensitivity of Glycerinated Cardiac Fibres to Calcium

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