Brain research
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Delayed injury following trauma to the central nervous system (CNS) may be due to the release or activation of endogenous factors. Endogenous opioid peptides have been proposed as one such class of injury factors, based on pharmacological studies demonstrating a therapeutic effect of naloxone and other opiate receptor antagonists following CNS injury. However, changes in brain opioid concentrations following injury have not been evaluated. ⋯ In the anterior pituitary, a significant increase in ir-End and a significant decrease in ir-Dyn was observed at 2 h following both levels of injury. Pathological damage to brain tissue after injury was most pronounced in those regions showing significant increases in ir-Dyn but not other opioids. In the medulla, the increase in ir-Dyn but not ir-End or ir-Enk was also significantly correlated with a fall in systemic mean arterial pressure (MAP) at 2 h following high- but not low-level injury.(ABSTRACT TRUNCATED AT 250 WORDS)