Effects of sevoflurane on contractile responses and electrophysiologic properties in canine single cardiac myocytes.
BACKGROUND
The effects of sevoflurane was examined on the contractile response, membrane potential, membrane ionic currents, and intracellular cyclic adenosine monophosphate (cAMP) in canine single ventricular myocytes.


METHODS
Contraction was measured by a video-edge detector, and membrane ionic currents were recorded using whole-cell voltage clamp technique. Intracellular cAMP was measured with radioimmunoassay method.


RESULTS
Sevoflurane (1.0-4.0%) decreased the contraction of single ventricular cells in a dose-dependent and reversible manner. Also, sevoflurane decreased the action potential plateau and shortened the duration of action potential. Sevoflurane reduced the peak Ca2+ currents (ICa) but did not show the use-dependent block. On the other hand, sevoflurane slightly reduced the Na+ currents (INa) only at a high concentration (4.0%). Intracellular cAMP concentration was reduced only at 4.0% sevoflurane.


CONCLUSIONS
The negative inotropic effect of sevoflurane is mediated via the inhibition of ICa in canine ventricular myocyte but not associated with reduced intracellular cAMP except at a high dose (4.0%).
Department of Anesthesiology, Toyama Medical and Pharmaceutical University, School of Medicine.
N
N
Hatakeyama
Y
Y
Momose
Y
Y
Ito
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D004987:Ethers / Q000494:pharmacology*; D005260:Female; D066298:In Vitro Techniques; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D008738:Methyl Ethers; D009200:Myocardial Contraction / Q000187:drug effects*; D009206:Myocardium / Q000166:cytology; D018408:Patch-Clamp Techniques; D011188:Potassium / Q000494:pharmacology; D000077149:Sevoflurane
D004987:Ethers; D008738:Methyl Ethers; D000077149:Sevoflurane; D000242:Cyclic AMP; D011188:Potassium; D002118:Calcium