EFFECTS OF METHADONE AND MORPHINE ON THE ELECTROENCEPHALOGRAM OF THE DOG

¹ U. S. Public Health Service Hospital, Lexington, Kentucky

1. The effects of small and large doses of methadone and morphine on the electroencephalogram were studied in unanesthetized and uncurarized dogs and in curarized dogs. The motor pattern of the convulsive seizures induced by large doses of these drugs was also observed in different dogs.

2. A "mercury cup" electrode is described which facilitates the repeated recording of electroencephalograms from the dura over the cerebral cortex in unanesthetized and uncurarized animals, without interference due to artifacts from the scalp and temporal muscles.

3. Small doses of methadone or morphine produce an admixture of fast and high voltage slow activity in cortical tracings. Large doses of either drug produce seizure discharges which may appear synchronously in cortical and basal tracings or in cortical tracings alone. The seizure discharges from cortical tracings were both of the spike and dome and sustained spike patterns. At times the former passed over into the latter without interruption. An "after-seizure" 25 per second low voltage discharge in the tracings from the sphenoid lead was not associated with activity in the cortical leads.

4. The motor pattern of seizures induced in dogs by large doses of methadone or morphine were essentially the same, although clonic movements were more prominent in the methadone convulsions. These seizures appeared much sooner after subcutaneous injection of methadone than after morphine.