3-Methoxy-4-hydroxy-phenylglycol sulfate (MOPEG-SO4) in ventricular and cisternal cerebrospinal fluid of dogs.

Cerebrospinal fluid was collected from the lateral ventricles and cisternal space from beagle dogs under light pentobarbital anesthesia. Homovanillic acid (HVA), 5-hydroxyindoleacetic acid (5-HIAA), and 3-methoxy-4-hydroxyphenylglyco-sulfate (MOPEG-SO4) levels in the liquor taken from these two regions were evaluated, and the ventricular-cisternal ratio (V/C) was calculated for each monoamine metabolite. A marked similarity in the V/C ratio of 6:1 for 5-HIAA and 5:1 for MOPEG-SO4, as compared to a much higher V/C ratio of 18:1 for HVA, perhaps reflects the more diffuse distribution of norepinephrine and serotonin, precursor amines, as compared to dopamine in the CNS and also emphasizes the probable existence of an active transport mechanism for the removal of MOPEG-SO4, as has been well documented for 5-HIAA and HVA.