MONOAMINE NEUROTRANSMITTERS AND THEIR METABOLITES IN THE MATURE RABBIT BRAIN FOLLOWING INDUCTION OF HYDROCEPHALUS

Functional and behavioral disturbances associated with hydrocephalus m ay be due in part to altered neurotransmitter function in the brain. H ydrocephalus was induced in adult rabbits by injection of silicone oil into the cisterna magna. These and controls were killed 3 days, 1 and 4 weeks postinjection. Tissue concentrations of norepinephrine, epine phrine, serotonin, dopamine, and the metabolites 5-hydroxyindoleacetic acid (5-HIAA), homovanillic acid (HVA), and 3,4-dihydroxyphenylacetic acid (DOPAC) levels were determined in fifteen brain regions using HP LC. There were decreases in hypothalamic and medullary dopamine, trans ient decreases in basal ganglia serotonin, increases in thalamic norad renaline, and increases in hypothalamic and thalamic epinephrine. Chan ges in the primary neurotransmitters may be attributable to damage of their axonal projection systems. Metabolite concentrations increased i n the cerebrum. Reduced clearance of extracellular fluid which accompa nies cerebrospinal fluid stasis may explain the accumulation of metabo lites.