Depletions of central norepinephrine by intraventricular xylamine in rats.

A series of neurochemical studies evaluated the selectivity of the depletions of norepinephrine produced by intraventricular injections of xylamine. Brain monoamines were assayed by liquid chromatography with electrochemical detection. With ether anesthesia, bilateral injections of 50 or 100 micrograms xylamine reduced hippocampal levels of norepinephrine and serotonin without affecting striatal dopamine or serotonin. The depletion of hippocampal norepinephrine was significant as soon as 24 h. Animals treated with the combination of 20 mg/kg fluoxetine and 100 micrograms xylamine had selective depletions of central norepinephrine with no significant changes in serotonin.