| Abstract: | Hydrocephalus is characterized by enlargement of the cerebral ventricles. The behavioral disturbances are, in some cases, rapidly reversible by surgical treatment suggesting that there may be a functional impairment of neurons. Hydrocephalus was induced in 3-week old rats by kaolin injection into the cisterna magna. Parietal cerebrum and striatum content of monoamine neurotransmitters and amino acids were assayed by high performance liquid chromatography (HPLC), 1, 2, or 4 weeks after induction of hydrocephalus. The ventricles exhibited progressive enlargement which was partially reversed by surgical treatment. Cerebral water content was increased at all stages. Increased levels of cerebral aspartate and glutamate suggest that there is the potential for excitatory neurotoxicity. The increase in cerebral taurine correlated negatively with the increase in water content. Cerebral concentrations of norepinephrine and serotonin, and its metabolite 5-HIAA, were increased at 1 and 2 weeks suggesting an increase in their turnover during the early stages of ventricular dilatation. Dopamine and its metabolite DOPAC were transiently diminished in the striatum at 1 and 2 weeks, respectively, suggesting that axonal projections from the brainstem may be impaired. We conclude that the effect of hydrocephalus on amino acids and monoamines varies regionally. Due to increased water content, there may be dilution effects in whole tissue, therefore, it is important to make determinations on the basis of protein content. |
