Effect of carotid body denervation on breathing in neonatal goats.
The objective of the present study was to determine in goats whether carotid body denervation (CBD) at 1-3 days of age causes permanent changes in breathing greater than those that occur after CBD in adult goats. Goats underwent CBD (n = 6) or sham CBD (n = 3) surgery at 1-3 days of age. In addition, one unoperated control animal was studied. Bolus intravenous injections of NaCN 2 days postsurgery verified successful CBD surgery. However, at 3, 11, and 18 mo of age, the CBD goats had regained a NaCN response that did not differ (P > 0.10) from that of intact goats. Intracarotid NaCN injections elicited a hyperpnea in the sham CBD but not the CBD goats. Only one animal exhibited highly irregular breathing [characterized by prolonged (>9-s) apneas] after CBD, and the irregularity disappeared by 3 mo of age. One CBD goat died at 35 days of age, and autopsy revealed that death was associated with pneumonia. After 3 mo of age, there were no statistically significant differences (P > 0.10) between sham and CBD goats in eupneic breathing, hypoxia and CO(2) sensitivity, and the exercise hyperpnea. It is, therefore, concluded that CBD at 1-3 days of age in goats does not appear to affect selected aspects of respiratory control after 3 mo of age, conceivably because of the emergence of other functional chemoreceptors that compensate for the loss of the carotid chemoreceptor.
Lowry
T F
TF
Departments of Physiology and Pediatrics, Medical College of Wisconsin, Zablocki Veterans Affairs Medical Center, and Program in Physical Therapy, Marquette University, Milwaukee, Wisconsin 53226, USA.
Forster
H V
HV
Pan
L G
LG
Korducki
M A
MA
Probst
J
J
Franciosi
R A
RA
Forster
M
M
D000818:Animals; D000831:Animals, Newborn / Q000502:physiology*; D001784:Blood Gas Analysis; D001794:Blood Pressure / Q000502:physiology; D002344:Carotid Body / Q000502:physiology*; D003714:Denervation; D006041:Goats / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology; D006935:Hypercapnia / Q000503:physiopathology; D000860:Hypoxia / Q000503:physiopathology; D009475:Neurons, Afferent / Q000502:physiology; D005082:Physical Exertion / Q000502:physiology; D015656:Respiratory Mechanics / Q000502:physiology*; D013997:Time Factors