Effect of atropine, propranolol, and atenolol on wave structure of heart rate oscillations in rats.
Were studied the effects of atropine and beta-adrenoblockers on the power of very low (<0.25 Hz), low (0.25-0.70 Hz), and high frequency (0.7-1.8 Hz) waves of the heart rhythm in wakeful rats. Atropine reduced the power of all waves in 100% cases. Propranolol on average decreased the power of very low frequency waves and increased the power of low and high frequency waves, although opposite effects were observed in many cases. Atenolol produced similar effects. Some animals demonstrated spontaneous moderation of respiratory rate to a level corresponding to low-frequency oscillations of the heart rhythm accompanied by elevation of the relative power of low frequency waves. Inconsistency of the effects of beta-adrenoblockers in rats can be related to variability of sympathetic tone and spontaneous deceleration of respiration with the corresponding changes of low frequency waves. Augmentation of the high frequency waves during application of beta-adrenoblockers is not related to their action on CNS.
Sergeeva
O V
OV
Department of Normal Physiology, Russian State Medical University, Moscow, Russia. alipov@practica.ru
Alipov
N N
NN
Smirnov
V M
VM
D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology; D001262:Atenolol / Q000494:pharmacology*; D001285:Atropine / Q000494:pharmacology*; D001341:Autonomic Nervous System / Q000187:drug effects; D004353:Drug Evaluation, Preclinical; D004562:Electrocardiography / Q000187:drug effects; D005260:Female; D006339:Heart Rate / Q000187:drug effects*; D008297:Male; D011433:Propranolol / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D012119:Respiration / Q000187:drug effects; D013057:Spectrum Analysis
D000889:Anti-Arrhythmia Agents; D001262:Atenolol; D001285:Atropine; D011433:Propranolol