The EEG effects of opioids injected icv were studied in rats implanted with electrodes in the cortex, caudata, amygdala and hippocampus. All of the compounds tested (β-endorphin, leu-enkephalin, dynorphin, morphine, morphiceptin, DALE, DSLET) induced spikes and electrical seizures. The potency of the preferential δ agonist DSLET was two orders of magnitude greater than that of the preferential μ agonist morphiceptin. The profile of action of dynorphin was more complex than other opiates, as it included diazepam EEG desynchronization in some cases, electrical seizures and, eventually, behavioral convulsions in others. A specific μ antagonist, β-FNA, blocked the EEG effect of all the opioids except morphine. Lithium pretreatment potentiated the induction of seizures by morphicetin but not by other agonists. The results suggest an involvement of the μ receptors in opioid-induced electrical seizure activity, and confirm that δ receptors may play a role as well.
|Original language||English (US)|
|Number of pages||17|
|Journal||Research Communications in Psychology, Psychiatry and Behavior|
|State||Published - Jan 1 1989|
ASJC Scopus subject areas
- Psychiatry and Mental health