Anaesthesia for studies of the cerebral circulation: a comparison of phencyclidine and althesin in the baboon.

The effects of phencyclidine on cerebral blood flow, cerebral metabolic rate for oxygen and carbon dioxide reactivity were compared with those of Althesin in six baboons. Under similar and stable levels (Stage 1) of electroencephalographic activity cerebral blood flow and the cerebral metabolic rate for oxygen were significantly less during the infusion of Althesin when compared with the values obtained during the infusion of phencyclidine. Reactivity to carbon dioxide was present and similar during the infusion of either drug.