Faculty Collaboration Database

Volatile anesthetics attenuate sympathomimetic actions on the guinea pig SA node. Anesthesiology 1988 Jun;68(6):887-94

Date

06/01/1988

Pubmed ID

2897808

DOI

10.1097/00000542-198806000-00009

Scopus ID

2-s2.0-0023882858 (requires institutional sign-in at Scopus site)   28 Citations

Abstract

The authors examined and compared the direct effects of three volatile anesthetic agents and three sympathomimetic agonists on transmembrane action potential (AP) characteristics and automaticity of sinoatrial (SA) nodal pacemaker cells. SA nodal tissue was isolated from guinea pig hearts and suffused in vitro with oxygenated Krebs-Ringer solution. Electrophysiologic variables measured were: amplitude of the AP, slopes of phase 4 and of phase 0 of the AP, AP duration, and spontaneous sinus rate. The authors found that 1 and 2 MAC equivalents of each anesthetic, 0.8 and 1.6 vol % halothane, 1.4 and 2.8 vol % isoflurane, and 1.7 and 3.4 vol % enflurane similarly depressed the slopes of phase 4 and 0 of the AP, prolonged AP duration, and slowed the sinus rate at 1 and 2 MAC equivalents. Isoproterenol, 0.25 microM, and epinephrine, 50 microM, maximally enhanced the slopes of phase 4 and 0 of the AP, shortened AP duration, and increased the sinus rate, but phenylephrine, 50 microM, only moderately increased the slope of phase 4 and the sinus rate. Each of the three anesthetics caused baseline depressions of phase 4 and phase 0 slopes and of automaticity of SA nodal cells; the fall in sinus rate was counteracted, but was not reversed maximally by increasing the concentrations of isoproterenol, epinephrine, or phenylephrine. Regression analyses of linearly transformed data showed that each of the anesthetics similarly depressed basal sinus rate, so that changes in rate produced with isoproterenol and epinephrine were not different from those observed with beta agonists in the absence of anesthetics.(ABSTRACT TRUNCATED AT 250 WORDS)

Author List

Stowe DF, Dujic Z, Bosnjak ZJ, Kalbfleisch JH, Kampine JP

Author

David F. Stowe MD, PhD Professor in the Anesthesiology department at Medical College of Wisconsin

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

Action Potentials
Adrenergic alpha-Agonists
Adrenergic beta-Agonists
Anesthetics
Animals
Enflurane
Epinephrine
Guinea Pigs
Halothane
In Vitro Techniques
Isoflurane
Isoproterenol
Phenylephrine
Sinoatrial Node