ELEVATED CONCENTRATIONS OF DOPAMINE SULFATE IN PLASMA OF COCAINE ABUSERS

This study investigated the effect of cocaine abuse on peripheral cate cholamines. Specifically, we measured the concentration of free dopami ne, dopamine sulfate, free norepinephrine, norepinephrine sulfate, fre e epinephrine and epinephrine sulfate in plasma samples obtained from the blood of a group of patients with cocaine addiction (N = 15). The concentrations of free and sulfoconjugated catecholamines in plasma we re measured by a radioenzymatic technique. The results of this study r evealed significant (P < 0.0001) elevation in plasma dopamine sulfate (8926 +/- 1204 pg/mL) of cocaine addicts upon admission to an in-patie nt treatment facility when compared with the level of this dopamine me tabolite in plasma of control subjects (2356 +/- 121 pg/mL). Furthermo re, there was a significant (P < 0.0001) relationship between elevatio n in plasma dopamine sulfate levels and severity of cocaine use among these patients, and in the majority of cases the plasma levels of dopa mine sulfate declined appreciably in time with abstinence from cocaine . In contrast, no appreciable difference was observed in the concentra tions of either free or sulfate-conjugated norepinephrine and epinephr ine in plasma of cocaine addicts as compared with controls. Difference s in plasma dopamine sulfate among these patients versus controls may be interpreted as a reflection of activation of extracellular dopamine metabolism associated with chronic cocaine exposure in humans.