Long-term impairment in the neurochemical activity of the sympathoadrenal system after neonatal hypoxia in the rat.
The study evaluates the long-term effect of neonatal hypoxia on the neurochemical activity of the sympathoadrenal system in the rat. One-day-old male pups were exposed to hypoxia (10% O2) for 6 d and thereafter reared under normoxia. Neonatal hypoxia reduced the body weight of 3- and 8-wk-old rats and did not change the blood pressure at 6 wk of age. In sympathetic ganglia, the content and/or turnover rates of norepinephrine were reduced in neonatal-hypoxic rats of 3 and 8 wk of age, but the content and turnover rates of dopamine were unaltered. The effect was not dependent on the type of ganglion. In the superior cervical ganglion, neonatal hypoxia had a selective effect on the type of catecholamine (dopamine versus norepinephrine), thus suggesting a selective-altered maturation of noradrenergic neurons, but presumably not of the dopaminergic small, intensely fluorescent cells. A long-term deficiency in adrenal activity was the consequence of neonatal hypoxia, as shown by the decrease in the content and turnover rate of dopamine. Neonatal hypoxia elicited a long-term decrease in the content and turnover rates of norepinephrine in heart and lungs but failed to induce a significant effect in kidneys. However, this effect was not tissue-specific. Data provide evidence that a hypoxic episode occurring during a critical period of development in the rat induces a long lasting decrease in the neurochemical activity of the sympathoadrenal system. These results are discussed in terms of their implications for human pathology.
Soulier
V
V
UMR 5578, Physiologie des régulations énergétiques, cellulaires et moléculaires, Faculté de Médecine Grange Blanche, Lyon, France.
Peyronnet
J
J
Pequignot
J M
JM
Cottet-Emard
J M
JM
Lagercrantz
H
H
Dalmaz
Y
Y
D000311:Adrenal Glands / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn; D002395:Catecholamines / Q000378:metabolism*; D004298:Dopamine / Q000378:metabolism; D004837:Epinephrine / Q000378:metabolism; D005728:Ganglia, Sympathetic / Q000378:metabolism*; D006801:Humans; D000860:Hypoxia / Q000378:metabolism*; D008297:Male; D009638:Norepinephrine / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D014018:Tissue Distribution
D002395:Catecholamines; D004298:Dopamine; D009638:Norepinephrine; D004837:Epinephrine