Abstract
Fetal and/or neonatal malnutrition has been reported to cause lifelong changes of the control of blood pressure and glucose control etc. according to Barker et al (Lancet 341:938-941.1993). The aim of the present study was to investigate whether chronic neonatal hypoxia could cause longterm changes of catecholamine (CA) turnover in the sympatho-adrenal system and the carotid bodies One day old male pups were exposed with their dams to mild hypoxia (10% O2) for 6 days and thereafter grew up under normoxia until sacrifice. Normoxic control and neonatal hypoxic rats were examined at 3 or 8 weeks with regard to CA turnover. The levels and turnover rates of dopamine (DA), norepinephrine(NE) were determined in sympathetic ganglia and their main target organs, the adrenals and the carotid bodies. After exposure to neonatal hypoxia the turnover rates of NE in the superior cervical, stellate and coeliac-mesenteric ganglia were significantly (p<0.05). reduced to 64.6%, 77.5 and 76% respectively at the age of 3 weeks as compared with the controls. In the 8 week old rats the turnover of NE remained significantly reduced but to a less extent in the superior and stellate ganglia. In the target organs, neonatal hypoxia elicited a long-lasting decrease in the turnover rates of NE in the hearts and lungs. The content of DA considered to be a reliable index of adrenal activity were decreased at 3 and 8 weeks of age. The DA content in the carotid bodies increased by 90% and 84% at 3 and 8 weeks respectively in the hypoxic rats. Our data provide evidence that a mild hypoxic episode occurring during a critical period of development is able to cause long-lasting effects.
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