DIFFERENCE IN RESPONSE OF D-2 RECEPTOR-BINDING BETWEEN C-11 N-METHYLSPIPERONE AND C-11 RACLOPRIDE AGAINST ANESTHETICS IN RHESUS-MONKEY BRAIN

The effects of anesthesia on dopamine D-2 receptor binding in the rhes us monkey brain were examined using positron emission tomography. The bindings of C-11-N-methylspiperone (NMSP) and C-11-raclopride (RAG) we re measured under controlled ketamine or isoflurane anesthesia. The bi nding of C-11-NMSP was significantly lower in the striatum anesthetize d with isoflurane than with ketamine. There was a smaller change in th e binding of C-11-RAC than of C-11-NMSP. These findings suggest that c hanges in C-11-NMSP or C-11-RAC binding induced by anesthetics were no t due solely to changes in the competition of endogenous dopamine.