Figure 1.

Effects of the suppression of glucocorticoids on extracellular concentrations of dopamine in the nucleus accumbens and on locomotor activity. Compared with animals with an intact glucocorticoid secretion (SHAM), animals in which endogenous glucocorticoids have been suppressed by adrenalectomy (ADX) showed lower levels of dopamine in basal conditions and after the injection (arrows) of either vehicle or morphine, morphine-induced locomotor activity was also reduced in ADX rats. Administration of corticosterone to ADX animals (ADX+CORT) reversed these effects.