[Age changes in concentrations of monoamines and related substances in the cerebrospinal fluid]

We studied age changes of concentrations of thirteen substances including monoamines, their precursors and metabolites in the cerebrospinal fluid, using high performance liquid chromatography. Cerebrospinal fluid was obtained from 106 subjects without neurological diseases (44.2 +/- 17.3 years) who underwent minor operations under lumbar anesthesia. Concentrations of dopamine, norepinephrine, tyrosine and 3-methoxy-4-hydroxy-phenylalanine were significantly increased with age, while concentrations of other monoamine precursors and metabolites were unchanged. There was a significant positive correlation between concentrations of the following substances: dopamine and norepinephrine; tyrosine and tryptophan; tyrosine and 3-methoxy-4-hydroxy-phenylalanine; tyrosine and 5-hydroxytryptophan; homovanillic acid and 5-hydroxyindoleacetic acid. Norepinephrine concentrations were positively correlated with concentrations of 3-methoxy-4-hydroxy-phenylglycol, whereas dopamine concentrations were not with homovanillic acid concentrations. The significance of these results was discussed with regard to age changes of transmitter secretion and metabolism, the binding capacity of receptors and cerebrospinal fluid kinetics of the measured substances.