Plasma and cerebrospinal fluid concentrations of neuropeptide Y, serotonin, and catecholamines in patients under propofol or isoflurane anesthesia

Propofol is a widely used anesthetic for both induction and maintenance of anesthesia during surgery. A strong feeling of hunger has been reported dur ing the early recovery period after propofol anesthesia. We have investigat ed the effect of propofol on appetite in 10 patients undergoing a craniotom y and in parallel measured neuropeptide Y (NPY), catecholamines, and seroto nin levels in the cerebrospinal fluid and plasma during anesthesia. Ten pat ients anesthetized with a volatile agent (isoflurane) served as a control g roup. Plasma NPY and catecholamines levels were not affected by surgery at any time. We observed a strong increase in NPY concentrations in the cerebr ospinal fluid independently of the anesthetic technique agent used, whereas catecholamines were unchanged. We found that serotonin concentrations decr eased significantly in the plasma (but not in the cerebrospinal fluid) of p atients treated by propofol when compared with the control group; this decr ease was associated with an increase of hunger early postoperatively. We co ncluded that the proappetite effect of propofol is mediated through a decre ase of serotonin at the peripheral level.