Endogenous opioid-like substances in perinatal asphyxia and cerebral injury due to anoxia.

Perinatal asphyxia is one of the major causes of cerebral injury in neonates. It may be due to the increased endogenous opioid-like substances (OLS) in the body. The levels of three OLS, namely leucine-enkephalin (LEK), beta-endorphin (beta-EP) and dynorphin A1-13 (DynoA1-13) of 44 cases with neonatal asphyxia were studied by radioimmunoassay. The OLS level in plasma and cerebral spinal fluid (CSF) were higher in asphyxiated group than those in the control group, especially in asphyxiated cases with fetal distress. The OLS levels of CSF were also higher in cases with cerebral injury than in those without cerebral injury, while the levels of OLS in plasma had no difference in these two groups. The relationship between OLS levels and asphyxia and cerebral injury is also discussed.