Catecholamines and their major metabolites in plasma and cerebrospinal fluid of man

In 36 patients undergoing elective surgery under spinal anesthesia, plasma and cerebrospinal fluid (CSF) concentrations of catecholamines and their major metabolic products were determined. The development of specific and sensitive radioenzymatic assays make these determinations possible. The levels of norepinephrine, epinephrine, and the O-methylated metabolite, normetanephrine, were greater in the plasma then the CSF, although the difference was significant for norepinephrine and epinephrine only (P less than 0.01 for both) On the other hand the levels of both deaminated metabolites dihydroxyphenylglycol (DOPEG) and dihydroxymandelic acid (DOMA) were greater in the CSF the in plasma, but the difference was significant for DOPEG only (P less than 0.01). Although there was a positive and significant correlation between the levels in plasma and CSF of all these compounds, their concentrations in CSF may reflect metabolism of catecholamines in the central nervous system.