Cortical EEG changes during the self-administration of phencyclinoids.
Female rats, implanted with cerebrocortical EEG recording electrodes, were trained to self-administer cocaine and then ketamine under a fixed ratio 10 schedule of reinforcement, during limited access sessions. Periodically, a single unit dose of either phencyclidine (0.5 mg/kg), ketamine (4 mg/kg) or 1-(1-phenylcyclohexyl)morpholine (PCM 4 mg/kg) was substituted for ketamine, while the cortical EEG was recorded. Spectrum quantities of samples of EEG, taken immediately before and after each injection, were subjected to a discriminant analysis. For each drug, the preinjection state of the EEG could be classified separately from the postinjection state, using specific EEG spectrum quantities from the global frequency range (0.1-20 Hz). Furthermore, the relevant EEG parameters, which described the change from pre- to postinjection states, were unique for each drug (phencyclidine: total power and complexity; ketamine: peak frequency, relative power and mobility; PCM: all parameters except peak frequency), indicating potential differences in the EEG, occurring with a level of intake of drug which was controlled by the subject. Overall, these data serve to model the changes in the EEG that occur during the self-administration of three phencyclinoids. Furthermore, the combination of EEG spectrum analysis with discriminant analysis is useful in detecting subtle differences in the effects of these three drugs on the EEG.
Marquis
K L
KL
Department of Pharmacology and Toxicology, University of Maryland School of Pharmacy, Baltimore 21201.
Gussio
R
R
Webb
M G
MG
Moreton
J E
JE
D000818:Animals; D002540:Cerebral Cortex / Q000187:drug effects*; D003042:Cocaine / Q000494:pharmacology; D004569:Electroencephalography; D005260:Female; D007649:Ketamine / Q000494:pharmacology; D010622:Phencyclidine / Q000008:administration & dosage* / Q000031:analogs & derivatives; D051381:Rats; D011919:Rats, Inbred Strains; D012055:Reinforcement Schedule; D012646:Self Administration
D007649:Ketamine; D003042:Cocaine; D010622:Phencyclidine