Faculty Collaboration Database

Differential effects of halothane and isoflurane on contractile force and calcium transients in cardiac Purkinje fibers. Anesthesiology 1994 Jun;80(6):1360-8

Date

06/01/1994

Pubmed ID

8010480

DOI

10.1097/00000542-199406000-00024

Scopus ID

2-s2.0-0028240548 (requires institutional sign-in at Scopus site)   11 Citations

Abstract

BACKGROUND: Halothane and isoflurane have been shown to differentially effect mechanisms of contraction in working myocardial fibers. The aim of this study was to compare effects of halothane and isoflurane on contractile force (CF) and Ca2+ transients in canine cardiac Purkinje fiber preparations.

METHODS: Fiber preparations (n = 29) were superfused with Krebs-Ringer solution and stimulated at 40-60 pulses/min at 30 degrees C in the absence and presence of 0.55% and 1.01% isoflurane or 0.27% and 0.78% halothane. Isometric tension (CF), and intracellular Ca2+ transients (luminescence, L) were measured after microinjecting the Ca2+ sensitive photoprotein aequorin into Purkinje fibers. Peak CF and peak L, rate of rise (slope) of CF and L, time to attain peak CF and L, and duration of CF and L at half-peak CF and L, were measured at 5 mM extracellular CaCl2. Changes in peak CF and peak L also were measured during incremental increases in CaCl2 from 3.6 to 9.0 mM.

RESULTS: Both anesthetics depressed peak CF and peak L and the rate of increase in peak CF and L in a concentration-dependent fashion, and effects of halothane were greater than those of isoflurane. Time to attain peak L and duration of L at half-peak L was decreased or unchanged by isoflurane and was increased by halothane, whereas time to attain peak CF and duration of CF at half-peak CF was shortened by both. The change in peak CF response as a function of the change in peak L with increasing extracellular CaCl2 was attenuated similarly by both halothane and isoflurane.

CONCLUSIONS: Halothane depresses peak CF and Ca2+ transients and prolongs Ca2+ transients more than does isoflurane at equivalent minimum alveolar concentration in Purkinje fibers. This suggests Ca2+ concentration is differentially altered by anesthetics in this tissue. Peak CF at equivalent peak Ca2+ transients, however, appears to be attenuated similarly by both anesthetics. These differences in anesthetic effect are qualitatively similar to those found in cardiac tissue of other species. These findings add to our understanding of effects of volatile anesthetics on contractile properties and myoplasmic Ca2+ in cardiac Purkinje fibers.

Author List

Stowe DF, Sprung J, Turner LA, Kampine JP, Bosnjak ZJ

Authors

Zeljko Bosnjak PhD, MS Emeritus Professor in the Medicine department at Medical College of Wisconsin
David F. Stowe PhD, MA, MA Emeritus Professor in the Anesthesiology department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Animals
Calcium
Dogs
Halothane
Isoflurane
Myocardial Contraction
Purkinje Fibers