title: Nutrient control of cardiac rate in infant rats: role of arterial baroreceptors.
abstract: 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.
mesh_terms: D000344:Afferent Pathways / Q000502:physiology; D000828:Animal Population Groups / Q000502:physiology*; D000818:Animals; D000833:Animals, Suckling / Q000502:physiology*; D001794:Blood Pressure; D002346:Carotid Sinus / Q000502:physiology; D003714:Denervation; D004567:Electrodes, Implanted; D005508:Food Deprivation / Q000502:physiology*; D006339:Heart Rate; D011311:Pressoreceptors / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D012018:Reflex / Q000502:physiology; D013997:Time Factors