La. Davies et al., Effects of isoflurane, sevoflurane, and halothane on myofilament Ca2+ sensitivity and sarcoplasmic reticulum Ca2+ release in rat ventricular myocytes, ANESTHESIOL, 93(4), 2000, pp. 1034-1044
Citations number
44
Categorie Soggetti
Aneshtesia & Intensive Care","Medical Research Diagnosis & Treatment
Background: The aim of this study was to describe and compare the effects o
f isoflurane, sevoflurane, and halothane at selected concentrations (i.e.,
concentrations that led to equivalent depression of the electrically evoked
Ca2+ transient) on myofilament Ca2+ sensitivity, sarcoplasmic reticulum (S
R) Ca2+ content, and the fraction of SR Ca2+ released during electrical sti
mulation (fractional release) in rat ventricular myocytes.
Methods: Single rat ventricular myocytes loaded with fura-2 were electrical
ly stimulated at 1 Hz, and the Ca2+ transients and contractions were record
ed optically. Cells were exposed to each anesthetic for 1 min. Changes In m
yofilament Ca2+ sensitivity were assessed by comparing the changes in the C
a2+ transient and contraction during exposure to anesthetic and low Ca2+. S
R Ca2+ content was assessed by exposure to 20 mM caffeine.
Results: Isoflurane and halothane caused a depression of myofilament Ca2+ s
ensitivity, unlike sevoflurane, which had no effect on myofilament Ca2+ sen
sitivity. All three anesthetics decreased the electrically stimulated Ca2transient. SR Ca2+ content was reduced by both isoflurane and halothane but
was unchanged by sevoflurane, Fractional release was reduced by both isofl
urane and sevoflurane, but was unchanged by halothane.
Conclusions: Depressed myofilament Ca2+ sensitivity contributes to the nega
tive inotropic effects of isoflurane and halothane but not sevoflurane. The
decrease in the Ca2+ transient is either responsible for or contributory t
o the negative Inotropic effects of all three anesthetics and is either pri
marily the result of a decrease in fractional release (isoflurane and sevof
lurane) or primarily the result of a decrease in SR Ca2+ content (halothane
).