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Interaction of isoflurane and cromakalim, a K ATP channel opener, on coronary and systemic haemodynamics in chronically instrumented dogs
Author(s) -
Sakai K.,
Zhang S.,
Ureshino H.,
Tomiyasu S.,
Sumikawa K.
Publication year - 2000
Publication title -
acta anaesthesiologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.738
H-Index - 107
eISSN - 1399-6576
pISSN - 0001-5172
DOI - 10.1034/j.1399-6576.2000.440915.x
Subject(s) - cromakalim , isoflurane , medicine , anesthesia , vasodilation , hemodynamics , potassium channel opener , cardiology , vascular resistance , potassium channel , agonist , receptor
Background: Although isoflurane has been shown to cause coronary and systemic vasodilation through K ATP channel activation, the interaction of K ATP channel openers and isoflurane has not been fully investigated. The present study was carried out to determine the haemodynamic actions of cromakalim, a K ATP channel opener, under the conscious state and during isoflurane anaesthesia in chronically instrumented dogs. Methods: Fourteen dogs were chronically instrumented to measure systemic and coronary haemodynamics. Each dog was randomly assigned to receive doses of either cromakalim, 4 and 10 μg · kg −1 i.v., or isoflurane, 2.1% end‐tidal (1.5 MAC), plus cromakalim, 4 and 10 μg · kg −1 i.v. Results: Cromakalim dose‐relatedly decreased mean arterial pressure and systemic vascular resistance and increased coronary blood flow in both conscious and anaesthetized states. With isoflurane, the duration of effects of cromakalim were prolonged. Isoflurane exerted an additive effect on the increase in coronary blood flow induced by a low‐dose cromakalim, whereas it did not influence the effect of a high‐dose cromakalim. The maximum rate of increase in left ventricular pressure and segment shortening were increased by cromakalim in the conscious state but unchanged during isoflurane anaesthesia. Conclusion: The results suggest that the coronary vasodilating effects of isoflurane and cromakalim are basically additive until cromakalim exerts the maximal effect, and that the action of cromakalim on the coronary vasculature is prolonged by isoflurane.