Developmental changes in reactivity of small femoral arteries in the fetal and postnatal baboon.
OBJECTIVE
We evaluated in vitro responsiveness of small arteries (internal diameter, 300 microm) from the femoral vascular bed of normal fetal (0.75-1.0 gestation) and neonatal (43-46 days) baboons to investigate whether the transition from fetal to neonatal life was associated with functional alterations in vasoconstrictor and vasodilator responses.


METHODS
The maximum response and sensitivity to potassium and to the constrictor agonists norepinephrine and U46619 (a thromboxane mimetic) were studied by in vitro myography. Vasodilator responses to the endothelium-dependent dilators acetylcholine and bradykinin were also investigated.


RESULTS
The maximum response to norepinephrine and U46619 and to potassium increased with gestational age, whereas the sensitivity to these vasoconstrictors was similar in all groups studied. In contrast, acetylcholine- and bradykinin-induced relaxation (median effective concentration and maximum response) did not change with age.


CONCLUSIONS
Receptor-mediated responses to a catecholamine, a prostanoid, and 2 endotheliumdependent vasodilators are similar in the fetal and neonatal baboon. The increase in maximal constriction with development, which is probably associated with growth or maturation of vascular smooth muscle, is likely to be a functionally important aspect in the development of cardiovascular function.
Laboratory for Pregnancy and Newborn Research, College of Veterinary Medicine, and the Department of Biomedical Sciences, Cornell University, Ithaca, NY 14853-6401, USA.
M A
MA
Anwar
K
K
Ju
C C
CC
Docherty
L
L
Poston
P W
PW
Nathanielsz
D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid / Q000494:pharmacology; D000109:Acetylcholine / Q000494:pharmacology; D000375:Aging; D000818:Animals; D000831:Animals, Newborn; D001920:Bradykinin / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000187:drug effects / Q000502:physiology; D005263:Femoral Artery / Q000187:drug effects / Q000196:embryology* / Q000254:growth & development*; D005865:Gestational Age; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000502:physiology; D009638:Norepinephrine / Q000494:pharmacology; D010215:Papio; D011188:Potassium / Q000494:pharmacology; D014661:Vasoconstriction / Q000187:drug effects; D014664:Vasodilation / Q000187:drug effects
D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; D000109:Acetylcholine; D011188:Potassium; D001920:Bradykinin; D009638:Norepinephrine