PREFRONTAL CORTEX AND NEOSTRIATUM SELF-STIMULATION IN RAT - DIFFERENTIAL EFFECTS PRODUCED BY APOMORPHINE

In a dose-response experiment the effects of i.p. injections of the dopamine receptor agonist apomorphine (0.075, 0.15, 0.3, 0.6 and 1.2 mg/kg) were studied on self-stimulation elicited from electrodes implanted in the medial and sulcal prefrontal cortex and caudate-putamen in the rat. From the medial and sulcal prefrontal cortex electrodes, apomorphine produced a dose-related decrease of self-stimulation rate which was consistent across animals. From the caudate-putamen electrodes, apomorphine produced a facilitatory effect in the majority of the animals at 1 or more doses. At other doses a decreased self-stimulation rate was observed. The clear and consistent effects of apomorphine on self-stimulation of the prefrontal cortex, together with other experimental evidence in the same line, suggest that dopamine is mediating self-stimulation of this cortical area.