Abstract
ABSTRACT: The present studies were conducted to examine the possibility that the increased vulnerability of the newborn brain to hypoxia may be due to age-related differences in vascular thickness and contractility. Segments of rostral choroidal (RC), posterior communicating (PC), basilar (B), and common carotid (CC) arteries were taken from 3- to 7-day-old lambs (n = 11) and adult sheep (n = 8) and studied using standard in vitro techniques. In lamb cerebral arteries, maturation was associated with significant increases in vessel thickness and tension generation. Because the increases in tension generation (77, 90, and 135% in PC, B, and RC segments) were proportionately greater than the corresponding increases in thickness (45, 75, and 34% in PC, B, and RC), force per unit area increased with maturation in the cerebral arteries. In the CC segments, the age-related increases in thickness (117%) were greater than the increases in tension generation (30%), such that average force per unit area was actually greater in the lamb than in the sheep. In response to hypoxia (PO2 < 15 torr), all vessels exhibited significant relaxation relative to normoxic controls, although the rates and magnitudes of relaxation varied considerably. In the sheep, the carotid exhibited rapid relaxation of small magnitude (21%), whereas the cerebral arteries relaxed more slowly and more completely (56,52, and 45% in PC, B, and RC). In contrast, the lamb carotid segments relaxed more slowly than the cerebral arteries. Although the average magnitude of relaxation in the lamb carotids (40%) was less than in the lamb cerebral vessels (69, 48, and 79% in PC, B, and RC), it was twice as great as that observed in the sheep carotids (21%). These data indicate that the pattern of response to hypoxia was markedly different in the lamb and sheep and suggest that the carotid artery may play a more important role in the regulation of cerebrovascular resistance in the newborn than in the adult. This may be of clinical importance in the newborn in which variations in cerebral perfusion pressure occur during hypoxia.
Similar content being viewed by others
Article PDF
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Pearce, W., Ashwal, S. Developmental Changes in Thickness, Contractility, and Hypoxic Sensitivity of Newborn Lamb Cerebral Arteries. Pediatr Res 22, 192–196 (1987). https://doi.org/10.1203/00006450-198708000-00019
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1203/00006450-198708000-00019
This article is cited by
-
The Contribution of δ1- and δ2-Opioid Receptors to Hypoxia-Induced Pial Artery Dilation in the Newborn Pig
Journal of Cerebral Blood Flow & Metabolism (1995)