EFFECTS OF INTRAVENOUS ANESTHETICS ON PHOSPHATIDYLINOSITOL TURNOVER IN RAT CEREBRAL CORTICAL PRISMS

Noradrenergic pathways in the brain have been thought to related to th e site of anesthetic action. Norepinephrine (NE) in the central nervou s system stimulates phosphatidylinositol turnover through alpha(1)-adr energic receptors. The present study was designed to examine the effec ts of intravenous anesthetics on NE-induced PI turnover in rat cerebra l cortical prisms. NE-induced inositol monophosphate (IP1) formation w as inhibited by droperidol (dose for 50% inhibition [ID50], 0.0258 +/- 0.00023 mu M [mean +/- SE]), fentanyl (2.36 +/- 0.0017), diazepam (2. 01 +/- 2.12), and thiamylal (2.31 +/- 1.94) in a dose-dependent manner , but was not affected by ketamine. Naloxone or flumazenil did not att enuate the inhibitory effect of fentanyl or diazepam on NE-induced IP1 formation. The results suggest that these effects on the PI turnover in the cortex may be related to their pharmacologic properties includi ng the anesthetic action.