Interaction of brain and intracardiac levels of rhythmogenesis hierarchical system at heart rhythm formation.
A single-stage bilateral conduction blockade of the vagus nerves (functional denervation) by constant anodal current was carried out in 13 dogs which are under anesthesia and 3-5 days after operation in chronic experiments. In anesthetized animals, "functional denervation" led to acceleration of the heart rhythm from 102.4+/-3.2 bmp to 123.8+/-4.4 bmp. In chronic dogs "functional denervation" led to transient stoppage of the heart--a preautomatic pause with duration of 2.7+/-0.2 sec. The heartbeats recommenced with the frequency of 89.0+/-3.4 bmp versus an initial rhythm of 118+/-1.5 bpm, i.e., a rhythm deceleration took place. We conclude that in a whole organism the heart rhythm pacemaker is determined by a brain level of the hierarchical system of rhythmogenesis, while the sinoatrial node plays the role of a latent pacemaker.
Pokrovskii
Vladimir M
VM
Normal Physiology Department, Kuban State Medical University, Sedin St., 4, Krasnodar, 350063, Russia. pokrovsky@ksma.kubannet.ru
Abushkevich
Valery G
VG
Gurbich
Dmitriy V
DV
Klykova
Mariya S
MS
Nechepurenko
Anatoliy A
AA
D000818:Animals; D017776:Autonomic Pathways / Q000502:physiology*; D001683:Biological Clocks / Q000502:physiology*; D001921:Brain / Q000502:physiology*; D004285:Dogs; D004558:Electric Stimulation; D006321:Heart / Q000294:innervation / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology*; D010507:Periodicity; D011930:Reaction Time / Q000502:physiology; D012849:Sinoatrial Node / Q000502:physiology; D013997:Time Factors; D014630:Vagus Nerve / Q000502:physiology