The effects of amiodarone on the sinus node activity of the rabbit heart.
The action of amiodarone (1.5 X 10(-5) M) on sinus node activity of spontaneously beating isolated right atria of rabbit at 30 degrees C was investigated using a microelectrode technique. The drug significantly increased the action potential duration and decreased the slope of diastolic depolarization, both effects leading to a reduction of the sinus rate. In contrast to beta-blocking agents, amiodarone reduced but did not completely abolish the adrenergic effects on the sinus node activity. It is concluded that the amiodarone-induced bradycarida observed in clinical trials might be due to a direct effect of the drug on the sinus node.
D000200:Action Potentials / Q000187:drug effects; D000638:Amiodarone / Q000494:pharmacology*; D000818:Animals; D001572:Benzofurans / Q000494:pharmacology*; D004347:Drug Interactions; D004837:Epinephrine / Q000494:pharmacology; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D066298:In Vitro Techniques; D008297:Male; D008839:Microelectrodes; D009638:Norepinephrine / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D011817:Rabbits; D012849:Sinoatrial Node / Q000187:drug effects*
D001572:Benzofurans; D011433:Propranolol; D000638:Amiodarone; D009638:Norepinephrine; D004837:Epinephrine