PMID: 8602669Feb 1, 1996Paper

Isoflurane and sevoflurane modulate inactivation kinetics of Ca2+ currents in single bullfrog atrial myocytes

Anesthesiology
K HirotaY Ito

Abstract

To clarify the mechanism(s) of anesthetic depression of myocardial Ca2+ currents, the effects of isoflurane and sevoflurane on the inactivation kinetics of Ca2+ current in single bullfrog atrial myocytes were studied. Freshly isolated bullfrog atrial myocytes were obtained with an enzymatic dispersion procedure. Ca2+ currents were recorded with a whole-cell voltage-clamp technique. Both isoflurane (1.25, 2.5, 5.0 vol%) and sevoflurane (2.5, 5.0 vol%) decreased the peak amplitude of Ca2+ current ICa with a minimal change in the time to peak and the reversal potential. The inactivation kinetics studies revealed that (1) isoflurane (2.5 vol%) and sevoflurane (5.0 vol%) markedly reduced the time constant of inactivation in ICa to 55% and 75% of control, respectively; (2) isoflurane (2.5 vol%) shifted the midpoint (V1/2) of steady-state inactivation curve of ICa toward negative by 2.3 mV; and (3) isoflurane (2.5 vol%) delayed the reactivation time constant of ICa to 119% of control. The further computer-simulation study demonstrated that the observed decrease of time constant by isoflurane (1.25, 2.5 vol%) and sevoflurane (2.5 vol%) can explain the reduction in amplitude of ICa. The depression of ICa by lower concentration of isoflu...Continue Reading

References

Apr 1, 1989·Acta Anaesthesiologica Scandinavica·K HirotaY Momose
Aug 1, 1985·Acta Anaesthesiologica Scandinavica·Y IkemotoJ Yoshitake
Dec 1, 1986·Computer Methods and Programs in Biomedicine·K Robinson, W Giles
Aug 1, 1981·Pflügers Archiv : European journal of physiology·O P HamillF J Sigworth
Oct 1, 1982·Pflügers Archiv : European journal of physiology·G Isenberg, U Klöckner
Feb 1, 1983·The Journal of General Physiology·J R Hume, W Giles
Sep 1, 1983·Pflügers Archiv : European journal of physiology·T Klitzner, M Morad

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Citations

Jan 22, 2000·Biochemical Pharmacology·C R JanC J Tseng
Apr 16, 1998·Anesthesia and Analgesia·I M NikonorovE Recio-Pinto
Jul 29, 2003·Anesthesiology·Igor M NikonorovEsperanza Recio-Pinto
Nov 25, 2005·Anesthesiology·Kevin J GingrichThomas J Blanck
Oct 29, 2000·Journal of Applied Physiology·A E Bartunek, P R Housmans

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