Intrinsic neural regulation of the heart in the chronic, conscious dog.
The present experiments were performed to examine the capability of the intrinsic cardiac nerves (ICN) to modify cardiac performance in the resting chronic, conscious dog. Control and cardiac-denervated dogs were instrumented for recording of left atrial (LA) and ventricular (LV) contractility, heart rate, and atrioventricular (AV) conduction time. Acetylcholine (ACh) and nicotine (Nic) were administered via an indwelling coronary artery catheter. Limited distribution from the injection site only allowed access to the LA, LV, and AV node. Both beta-blockade with timolol and cardiac denervation were used to separate direct effects of ICN stimulation from indirect (e.g., reflex) effects. ACh produced the expected negative inotropic and dromotropic changes. ICN stimulation with Nic caused large decreases in LA on but only trivial effects on the LV. We concluded that the ICN has limited effects on cardiac performance in the resting animal under minimal sympathetic drive. It is likely, however, that the ICN is capable of significantly depressing cardiac function under conditions of elevated sympathetic tone as would be encountered in exercise.
Priola
D V
DV
Department of Cell Biology and Physiology, University of New Mexico School of Medicine, Albuquerque, New Mexico 87131, USA.
Cao
X
X
Anagnostelis
C
C
Bassenge
E
E
D000109:Acetylcholine / Q000494:pharmacology; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D016279:Atrial Function, Left / Q000187:drug effects / Q000502:physiology; D001283:Atrioventricular Node / Q000187:drug effects* / Q000502:physiology; D018678:Cholinergic Agents / Q000494:pharmacology; D003714:Denervation; D004285:Dogs; D005260:Female; D006321:Heart / Q000294:innervation*; D006339:Heart Rate / Q000187:drug effects* / Q000502:physiology; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects* / Q000502:physiology; D009538:Nicotine / Q000494:pharmacology; D013999:Timolol / Q000494:pharmacology; D016277:Ventricular Function, Left / Q000187:drug effects / Q000502:physiology
D000319:Adrenergic beta-Antagonists; D018678:Cholinergic Agents; D009538:Nicotine; D013999:Timolol; D000109:Acetylcholine