Previously we have reported that sub-chronic administration of nandrolone modifies reward-related neurochemical effects of psychomotor stimulant drugs of abuse. The aim of the present study was to evaluate whether the ability of nandrolone (19-nortestosterone) to attenuate the effects of amphetamine depends on activation of androgen (AR) or estrogen receptors (ER). We used an in vivo microdialysis technique in fully conscious rats to monitor whether administration of the AR-antagonist flutamide (7x50 mg/kg) or the ER-antagonist clomiphene (7x20 mg/kg), attenuates nandrolone-induced modulation of dopaminergic and serotonergic effects of acute injections of amphetamine (1 mg/kg). Dopamine (DA), 5-hydroxytryptamine (5-HT) and their metabolites were measured from the samples using high performance liquid chromatography (HPLC). Blocking the androgen receptors with flutamide abolished the attenuating effect of nandrolone pre-treatment on amphetamine-induced elevation of extracellular DA concentration. Blocking the estrogen receptors with clomiphene did the same but to a lesser extent. In conclusion, the results of this study show that the ability of nandrolone to attenuate the effects of amphetamine depends on activation of androgen receptors or to a lesser extent, on estrogen receptors.
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