Mechanism of myocardial protection by isoflurane. Role of adenosine triphosphate-regulated potassium (KATP) channels. Anesthesiology 1996 Oct;85(4):794-807; discussion 27A
Date
10/01/1996Pubmed ID
8873550DOI
10.1097/00000542-199610000-00015Scopus ID
2-s2.0-0029909986 (requires institutional sign-in at Scopus site) 170 CitationsAbstract
BACKGROUND: The mechanism of the protective actions of volatile anesthetics in ischemic myocardium has not been clearly elucidated. The role of myocardial adenosine triphosphate-regulated potassium (KATP) channels in isoflurane-induced enhancement of recovery of regional contractile function after multiple brief occlusions and reperfusion of the left anterior descending coronary artery (LAD) was studied in dogs anesthetized with barbiturates.
METHODS: Dogs (n = 32) were instrumented to measure left ventricular and aortic blood pressure, cardiac output, LAD coronary blood flow velocity, and subendocardial segment length. Regional myocardial perfusion was measured using radioactive microspheres. Hemodynamics and percentage segment shortening (%SS) in the LAD perfusion territory were evaluated after instrumentation was complete; after pretreatment with the KATP channel antagonist, glyburide (0.05 mg/kg-1) or drug vehicle (polyethylene glycol in ethyl alcohol; control experiments); and in the presence or absence of 1 MAC isoflurane administered for 30 min before and during five 5-min occlusions and reperfusion of the LAD in four experimental groups. Isoflurane was discontinued at the onset of the final reperfusion period. Measurements of hemodynamics, %SS, and myocardial perfusion were repeated at several intervals during 180 min after reperfusion of the LAD.
RESULTS: Left anterior descending coronary artery occlusion caused regional dyskinesia during each 5-min occlusion in each dog. Control and glyburide-pretreated dogs demonstrated poor recovery of %SS by 180 min after reperfusion (2 +/- 10 and 7 +/- 6% of baseline, respectively). In contrast, dogs anesthetized with isoflurane exhibited complete recovery of function (%SS) by 180 min after reperfusion (82 +/- 8% of baseline). Enhanced recovery of regional contractile function by isoflurane was abolished by pretreatment with glyburide 180 min after reperfusion (16 +/- 10% of baseline). Improvement of functional recovery of stunned myocardium by isoflurane, and the blockade of this action by glyburide, was not associated with changes in hemodynamics or regional myocardial perfusion.
CONCLUSIONS: The results indicate that isoflurane prevents decreased systolic shortening caused by multiple episodes of ischemia and reperfusion. These actions result in improved recovery of contractile function of postischemic, reperfused myocardium and are mediated by isoflurane-induced activation of KATP channels.
Author List
Kersten JR, Schmeling TJ, Hettrick DA, Pagel PS, Gross GJ, Warltier DCAuthor
Paul S. Pagel MD, PhD Professor in the Anesthesiology department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
Adenosine TriphosphateAnesthetics, Inhalation
Animals
Coronary Circulation
Dogs
Drug Interactions
Female
Glyburide
Heart
Hemodynamics
Isoflurane
Male
Myocardial Contraction
Myocardial Ischemia
Myocardial Reperfusion Injury
Myocardium
Potassium Channel Blockers
Potassium Channels