Effects of ohmefentanyl on the content of endorphin in pituitary and brain areas of rats

Ohmefentanyl was first developed in Shanghai Institute of Materia Medica, Chinese Academy of Sciences. It has been known that ohmefentanyl ip caused analgesia at 3 microg/kg, and catalepsy at 15 microg/kg. In the present paper, we studied the relationship of ohmefentanyl-inudced analgesia and catalepsy with the contents of dynorphin-A1-13, dynorphin-B, metenkephalin and beta-endorphin in pituitary and other brain areas of rats. The results of radioimmunoassay showed that in pituitary all the peptides mentioned were reduced at 3 microg/kg and raised at 15 microg/kg in comparison with 3 microg/kg group; in striatum the levels of dynorphin-A1-13 and dynorphin B did not change significantly at 3 microg/kg but increased at 15 microg/kg. The content of net-enkephalin were reduced at analgesia and raised at catalepsy; in spinal cord dynorphin-B and met-enkephalin were increased dose-dependently; in hippocampus and hypothalamus the contents of peptides varied in different ways, depending on the dose of ohmefentanyl and kinds of peptide measured.