Opioid peptides, particularly dynorphin, after amygdaloid-kindled seizures

The influence of amygdaloid kindling on brain and pituitary content of immunoreactive dynorphin (IR-DYN) and other opioid peptides was studied in rabbits. The kindling was very effective in increasing the hippocampal levels of IR-DYN, alpha-neoendorphin and Leu-enkephalin, but remained without any significant effect on the levels of IR-DYN and beta-endorphin in the majority of brain structures studied. The concentration of IR-DYN in the hippocampus remained at the control level throughout the development but was increased dramatically after completion of kindling. Biochemical alterations persisted for at least one month following the completion of kindling. The obtained results suggest that the hippocampal IR-DYN and related peptides may play some role in the maintenance of amygdaloid-kindled seizures.