Cardiac effects of propofol and its interaction with autonomic nervous system in isolated, cross-circulated canine atria.
OBJECTIVE
The effects of propofol on sinoatrial pacemaker activity and myocardial contractility and its interaction with the autonomic nervous system were investigated in isolated, cross-circulated right atrial canine preparations.


METHODS
An isolated right atrial preparation was perfused with heparinized arterial blood from an anesthetized support dog and changes in atrial rate and atrial contractile force were recorded.


RESULTS
Propofol (30-1000 microg) and thiopental (30-1000 microg), injected into the sinus node artery of the isolated atrium, induced dose-dependent decreases in atrial rate and contractile force. The negative chronotropic and inotropic effects of propofol were greater than those of thiopental. The propofol-induced negative chronotropic and inotropic responses were not inhibited by atropine. Propofol had no effects on the cardiac responses to acetylcholine, norepinephrine, and the intracardiac parasympathetic nerve stimulation which activates ganglionic nicotinic acetylcholine receptors.


CONCLUSIONS
These results indicate that: (a) propofol directly depresses sinoatrial pacemaker activity and myocardial contractility, (b) the negative chronotropic and inotropic effects of propofol do not involve activation of muscarinic receptors, and (c) propofol has little interaction with the autonomic nervous system at the effector site.
Nagashima
Y
Y
Department of Pharmacology, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto 390-8621, Japan.
Furukawa
Y
Y
Hirose
M
M
Chiba
S
S