BRAIN AND SPINAL CORD METABOLIC ACTIVITY DURING PROPOFOL ANAESTHESIA

We have investigated the effects of propofol anaesthesia on the metabolic activity pattern of 35 regions of the rat brain and cervical spinal cord using the uC-2-deoxyglucose technique. Anaesthesia was produced by an i.v. bolus of the commercial preparation of the drug (8 mg kg-') and maintained with successive bolus ad-ministrations of 6 mg kg''. Functional activity values (expressed as rates of local utilization of glucose) were reduced in 31 grey matter and two white matter structures in a propofol group relative both to saline-injected and vehicle-injected (aqueous emulsion containing 10% soya bean oil, 1.2 % egg phosphatide and2.25% glycerol) controls. Values from the two control groups did not differ significantly. Propofol-induced depression of metabolic activity was present in central nervous system regions be-longing to sensory (auditory, visual and somato-sensory), motor and limbic systems, including spinal cord grey matter. Mean percentage de-creases ranged from 40 % (vestibular nuclei) to 76 % (cingulate cortex). Although these values may be slightly overestimated because of the modest increase in PaCOj in the anaesthetized group, propofol appeared to elicit generalized reduction of central nervous system functional activity