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Catecholamine and endorphin responses to delivery in term and preterm lambs
J F Padbury1, Y Agata, D H Polk
1UCLA School of Medicine, Harbor-UCLA Medical Center, Torrance.
Developmental Pharmacology and Therapeutics
|January 1, 1988
Summary
Neonatal lambs show increased catecholamines and endorphins at birth. Preterm lambs exhibited higher peak levels of norepinephrine and epinephrine, suggesting altered stress responses during adaptation to extrauterine life.
Area of Science:
- Neonatal Physiology
- Endocrinology
- Perinatal Medicine
Background:
- Catecholamine and endorphin surges occur at birth in mammals.
- Regulation of catecholamine secretion is not fully understood.
- Endogenous opiates may influence catecholamine secretion.
Purpose of the Study:
- To compare plasma catecholamine and endorphin levels at birth in term and preterm lambs.
- To investigate the relationship between catecholamines and endorphins during neonatal adaptation.
Main Methods:
- Measurement of catecholamines (norepinephrine, epinephrine) and beta-endorphin-like immunoreactivity (beta-ELI) in term and preterm lambs.
- Lambs were studied following umbilical cord cutting.
- Preterm lambs received surfactant therapy.
Main Results:
- Circulating norepinephrine and epinephrine significantly increased after umbilical cord cutting in both groups.
- Peak norepinephrine and epinephrine levels were higher and occurred later in preterm lambs compared to term lambs.
- Baseline beta-endorphin-like immunoreactivity was lower in preterm lambs, but peak levels post-cord cutting were significantly higher than in term lambs.
Conclusions:
- Preterm lambs display distinct patterns of catecholamine and endorphin release at birth compared to term lambs.
- These differences may reflect altered physiological adaptation to extrauterine life in preterm neonates.
- Further research is needed to elucidate the regulatory mechanisms and clinical implications of these findings.