ACUTE FLUMAZENIL ADMINISTRATION - EFFECTS ON SEROTONIN, 5-HYDROXYINDOLEACETIC ACID, NORADRENALINE, NORMETANEPHRINE AND GAMMA-AMINOBUTYRIACID ENDOGENOUS LEVELS IN HYPOTHALAMUS AND CEREBRAL FRONTAL-CORTEX

1.- Neurochemical effects of flumazenil on hypothalamus and cerebral frontal cortex were studied. 2.- Endogenous levels of noradrenaline (NA), normetanephrine (NMN), serotonin (5-HT), 5-hydroxyindoleacetic acid (5-HIAA) and gamma-aminobutyric acid (GABA) were measured in hypothalamus and frontal cerebral cortex of rat brain 30 min after ip. treatment with 5 mg kg-1 of flumazenil . 3.- Thirty minutes after treatment with flumazenil we found an increase in 5-HIAA hypothalamic levels. A separated group of animals treated with 1 mg kg-1 of diazepam showed the same effect 30 min after i.p. injection of the drug. Flumazenil failed to modify GABA, NA and NMN hypothalamic levels. 4.- None of the treatments exerted any effect on cerebral cortical neurotransmitters levels. 5.- It may be concluded that flumazenil acts as a selective partial agonist on serotonergic hypothalamic pathways.