AJP - Regulatory, Integrative and Comparative Physiology, Vol 249, Issue 4 443-R448, Copyright © 1985 by American Physiological Society
Nutrient control of cardiac rate in infant rats: role of arterial baroreceptors
M. A. Hofer
A surgical procedure is described for the deafferentation of carotid sinus
(CS) and aortic depressor (AD) baroreceptors in 2-wk suckling rats.
Baroreflex testing in unanesthetized pups showed that cardiac rate
responses to acute elevations of blood pressure were reduced to less than
9% of controls after combined denervation (CSAD), 28% after AD and 47%
after CS denervation at 4 h. After 24 h of nutrient deprivation, resting
cardiac rates of sham operated controls fell a mean of -148 beat/min,
significantly more than CS, AD, or CSAD groups (P less than 0.01).
Baroreflex test responses in individuals correlated significantly with
their later responses to nutrient deprivation (r = 0.67, P less than 0.01).
There were no significant differences in base-line cardiac rate, systolic
blood pressure, or cardiac rate during 24 h intragastric milk infusion
between deafferented and control pups. These experiments suggest that
arterial baroreceptors are important in the cardiovascular adjustments
after nutrient deprivation in suckling rats.
