DETERMINATION OF ENDOGENOUS CONCENTRATIONS OF NOREPINEPHRINE AND DOPAMINE AND THEIR RATES OF SYNTHESIS IN A SINGLE MOUSE-BRAIN - BIPHASIC EFFECTS OF (+)-AMPHETAMINE
A method is described that possesses sufficient sensitivity to permit the simultaneous fluorometric assay of endogenous concentrations of tyrosine, dopamine and norepinephrine, and the measurement of the estimated rate of synthesis of 3H-dopamine and 3H-norepinephrine from 3H-tyrosine in a single mouse brain. (+)-Amphetamine elicited a biphasic effect reducing the estimated rate of synthesis of dopamine and norepinephrine at 5 mg/kg, while lowering the endogenous concentrations of these catecholamines and increasing their rates of synthesis at 15 mg/kg.