Time course for development of vagal inhibition of the heart in neonatal rats
Heart rate was recorded in anesthetized rats 1, 3 and 7 days after birth, and the cut peripheral end of the right vagus nerve stimulated electrically at frequencies of 5, 10, 20 and 40 Hz. Control heart rate increased from 344 ± 8 beats/min on eay one to 490 ± 10 beats/min on day seven. Stimulation 6-24 hours after birth slowed the heart rate. At 3 days, slowing was more marked at all frequencies and greatly enhanced at 20 and 40 Hz. It is concluded that efferent cardiac vagal fibers conduct action potentials and that ganglionic and post-ganglionic neurotransmission is established in rats within 6 hours after birth. © 1978.
Volume / Issue
Start / End Page
International Standard Serial Number (ISSN)
Digital Object Identifier (DOI)