Faculty Collaboration Database

Xenon does not alter cardiac function or major cation currents in isolated guinea pig hearts or myocytes. Anesthesiology 2000 Feb;92(2):516-22

Date

02/26/2000

Pubmed ID

10691240

DOI

10.1097/00000542-200002000-00035

Scopus ID

2-s2.0-0033960742 (requires institutional sign-in at Scopus site)   71 Citations

Abstract

BACKGROUND: The noble gas xenon (Xe) has been used as an inhalational anesthetic agent in clinical trials with little or no physiologic side effects. Like nitrous oxide, Xe is believed to exert minimal unwanted cardiovascular effects, and like nitrous oxide, the vapor concentration to achieve 1 minimum alveolar concentration (MAC) for Xe in humans is high, i.e., 70-80%. In the current study, concentrations of up to 80% Xe were examined for possible myocardial effects in isolated, erythrocyte-perfused guinea pig hearts and for possible effects on altering major cation currents in isolated guinea pig cardiomyocytes.

METHODS: Isolated guinea pigs hearts were perfused at 70 mm Hg via the Langendorff technique initially with a salt solution at 37 degrees C. Hearts were then perfused with fresh filtered (40-microm pore) and washed canine erythrocytes diluted in the salt solution equilibrated with 20% O2 in nitrogen (control), with 20% O2, 40% Xe, and 40% N2, (0.5 MAC), or with 20% O2 and 80% Xe (1 MAC), respectively. Hearts were perfused with 80% Xe for 15 min, and bradykinin was injected into the blood perfusate to test endothelium-dependent vasodilatory responses. Using the whole-cell patch-clamp technique, 80% Xe was tested for effects on the cardiac ion currents, the Na+, the L-type Ca2+, and the inward-rectifier K+ channel, in guinea pig myocytes suffused with a salt solution equilibrated with the same combinations of Xe, oxygen, and nitrogen as above.

RESULTS: In isolated hearts, heart rate, atrioventricular conduction time, left ventricular pressure, coronary flow, oxygen extraction, oxygen consumption, cardiac efficiency, and flow responses to bradykinin were not significantly (repeated measures analysis of variance, P>0.05) altered by 40% or 80% Xe compared with controls. In isolated cardiomyocytes, the amplitudes of the Na+, the L-type Ca2+, and the inward-rectifier K+ channel over a range of voltages also were not altered by 80% Xe compared with controls.

CONCLUSIONS: Unlike hydrocarbon-based gaseous anesthetics, Xe does not significantly alter any measured electrical, mechanical, or metabolic factors, or the nitric oxide-dependent flow response in isolated hearts, at least partly because Xe does not alter the major cation currents as shown here for cardiac myocytes. The authors' results indicate that Xe, at approximately 1 MAC for humans, has no physiologically important effects on the guinea pig heart.

Author List

Stowe DF, Rehmert GC, Kwok WM, Weigt HU, Georgieff M, Bosnjak ZJ

Authors

Wai-Meng Kwok PhD Professor in the Anesthesiology department at Medical College of Wisconsin
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
Anesthetics, Inhalation
Animals
Bradykinin
Calcium Channels, L-Type
Guinea Pigs
Heart
In Vitro Techniques
Ion Channels
Membrane Potentials
Myocardium
Oxygen Consumption
Patch-Clamp Techniques
Potassium Channels
Potassium Channels, Inwardly Rectifying
Sinoatrial Node
Sodium Channels
Xenon