[Adaptation disorders in newborn animals: pathogenesis and therapy. Review article]

The sympathoadrenal system of the neonate is stimulated during parturition and immediately after birth. Endogenous opioid peptides can be regarded as partial catecholamine antagonists. They have an inhibitory action on the respiratory center but may also lead to a redistribution of cerebral blood flow in favour of certain essential brain areas. The acidosis seen in connection with neonatal asphyxia stimulates a further release of catecholamines as well as opioid peptides. The therapeutic approach should lead to a rapid normalisation of respiration.